Peter Fonda has a perm, and a fake beard.
MGM Home Entertainment released this film as "Killer Force" on DVD in 2013 as part of the 12 Action Adventure Movies 3-Disc set. It's the first release since the VHS era.
Three cast members appeared in James Bond movies. Telly Savalas was Ernst Stavro Blofeld in On Her Majesty's Secret Service (1969). Sir Christopher Lee was Francisco Scaramanga in The Man with the Golden Gun (1974). Maud Adams appeared in three Bond movies as three different characters: as Andrea Anders in The Man with the Golden Gun (1974), as the title character in Octopussy (1983), and appeared uncredited in A View to a Kill (1985).
Both director Val Guest and actor Christopher Lee were staples for Hammer Films, but neither had worked together until this movie, which of course was not a Hammer Film.
The title is not Killer Force, it's The Diamond Mercenaries, as shown in the film's opening credits. Killer Force was a reissue title, most likely to boost rentals during the VHS boom.