Depending on your angle, this is either the first Wembley of an exciting new era, or a wake for a special event that will be special no more.
In one sense, the old magic has already gone. The Challenge Cup final as the climax of the season is a thing of the past, because, while it occupies the same place in the calendar, it comes early in the new summer campaign, rather than at the end of the traditional winter season.
This year's competition, despite being largely played in the hiatus between two league seasons, has maintained its shape and momentum. Indeed, the profile of the Cup has benefited from having February and March to itself, not to mention the freshness that comes from the absence, after eight years, of Wigan.
Wembley will be full, or very close to it, on Saturday. For all the feverish promotion of Super League, the Cup - and particularly the Wembley final - retains its grip on the imagination.
This was not always the case. The radical decision to take the final to London in 1929 was bitterly opposed in some quarters. Albert Rosenfeld, one of the game's greatest wingers and still the record try-scorer in a season, was typical of many who thought it an affront and never went to a final again.
Early crowds hovered around the 40,000 mark and for one year - 1932 - the final went back north, to Wigan.
It was the post-war crowd boom that carried Wembley onwards and upwards, with the Bradford-Halifax final of 1949 filling the stadium for the first time. The crowd limit was set at a slightly lower level than for the football final on the principle that, man for man, rugby league followers were bulkier.
The post-war boom was also notable for the drawn final in 1954 and the world record crowd - officially 102,569, unofficially a lot more than that at Odsal, home of this year's finalists, Bradford, for the replay between Warrington and Halifax.
By this stage, the Challenge Cup final was massively outdrawing any other rugby league match and had become not just an occasion for fans of the two finalists, but a rallying point for the game's devotees from all over its heartland.
National television and a game like the 1965 final between Wigan and Hunslet, then hailed as the best ever, raised the profile of the event still further, to the extent that it was asked whether it was really healthy for it to take such priority over all other competitions.
They were hardly concerned about such niceties in 1971, however, when Leigh became the most surprising winners in Cup history, beating the unbackable favourites, Leeds, in a final during which Syd Hynes became the first player to be sent off at Wembley.
Folklore has it that his "victim", the endlessly wily Alex Murphy, winked at the crowd as he was carried off on a stretcher. Whatever the truth of that, Murphy was fully recovered in time to receive the Cup from Reginald Maudling.
Although Hynes was the first to walk off Wembley alone, the stadium had claimed a human sacrifice three years earlier, when Don Fox, who had already won the Lance Todd Trophy as the final's best player, missed the simplest of conversions that would have given Wakefield Trinity victory over Leeds.
It was known as the Watersplash final, but is remembered for Fox's desolation (it took him years to get over it), Eddie Waring's unusually spare and eloquent "Poor lad!", and the inane questioning of the suffering kicker by a youthful David Coleman.
The Eighties will be remembered for the 1985 final between Wigan and Hull, beyond any question the finest and most gripping. The after-match moment of communion between the Parramatta and Australia team-mates, Brett Kenny and Peter Sterling, is my own most evocative Wembley memory.
The sublime, effortless running of Kenny for victorious Wigan had brought him the Lance Todd; the exhausted Sterling had, if anything, played even better in a losing cause.
Three years later, Wigan embarked on a domination of the code's big day that continued until this year and their defeat in the fifth round at Salford. After their recent monopoly, their absence this time reinvigorates the occasion. It will be quite like old times to go down Wembley Way not knowing who is going to win.
But what of the future? Wembley is an overpriced, inadequate stadium, but the weekend in London is the pivotal one of the rugby league season. Can it remain such under the blueprint that is in place for succeeding seasons?
Much like the Government with the National Health Service, the Rugby League declares "the Cup is safe with us" without anyone really believing them.
Their mistake at headquarters is to imagine that the important thing is the month of the year in which the final is played. A final in April or May, two months into a summer season with previous rounds played as a pre-season pipe-opener based on groups, will be a betrayal of all that is good in the Cup's traditions.
Leaving windows in the Super League programme for a clean, straight knockout leading to a final in, say, August, would maintain those traditions, as well as extending a season which is now too short.
Teams which have lost four Super League matches this time have, in essence, seen their seasons end after a month. They cannot even say, in time-honoured fashion: "Ah well, there's always the Cup."