Armstrong, from East Dean, Sussex, will umpire the men's singles final, scheduled for Sunday, while Shales, from Teddington, Middlesex, will umpire tomorrow's women's singles.
It will be Armstrong's second men's singles final, for he was also in charge of the 1988 final between Stefan Edberg and Boris Becker.
Shales, who has been umpiring at Wimbledon since 1960, first took a women's singles final in 1978 when Martina Navratilova won the first of her nine victories by beating Chris Evert.
Bobby Wilson, who reached the quarter-finals at Wimbledon four times between 1958 and 1963 is honest enough to admit that the general standard of play today is far higher than in his day.
But the former British Davis Cup player thinks today's professionals have a much easier life than when he was striving to reach the top.
"Nowadays, the players run their own tour and can go anywhere, do anything and are entirely independent," he said.
"In my day, the national associations ruled the roost and woe betide you if you stepped out of line. You only went abroad with permission from your national association and did as you were told."
A conversation overheard in the Press Association Centre Court gallery today:
A man walked in, looked round and said: "I've come here because someone wants to do an interview with Pat Cash."
The steward in charge, firefighter Bobby Gorman of the London Fire Brigade Western Command, replies: "You want to do an interview with Pat Cash?"
The man staggered back and said: "I am Pat Cash." The result: no interview.Reuse content