Their costumes reflected uniforms during the Revolutionary War period. I believe the short one is Charlie Coe. The pic is kind of small, but I think that's who that is, depending on what year that album came out.

Freddie Weller, who was fairly successful as a country/western singer in the 70s was also a member.

Mark Lindsay (the lead singer) wore his hair in a pony tail and supposedly had the longest hair of any rock/pop singer of their time (middle to late sixties). He was always getting flack about it.