NOTE: - Since the programs are similar or the same (as in the case of the PRAY Awards) for girls and boys in Boy Scouting, 4H, Girl Scouting, Campfire, etc., a female Venturer or Adult Leader who earned her religious award as a youth may wear the purple square knot on her uniform even though it was not earned as a member of the BSA. (My daughter Darby in New Mexico does this!!) Per Mike Walton of www.USScouts.org, this applies to BOTH MALES AND FEMALES, youth and adult. If you earned a youth religious emblem as a youth member, whether or not it was earned or received as a BSA member does not matter. The youth religious emblem square knot represents ANY AWARD which youth members earned or received -- period. So yes, a Girl Scout, 4Her, or Royal Ranger/Missionette who earned a youth religious emblem in those programs and then either becomes an adult or youth member of the BSA (to include Venturing/Sea Scouting) may wear that emblem formally with the BSA's field uniforms; and informally wear the square knot insignia on the uniform shirt. Mike says he has been told when the next edition of the Uniform Guide for 2012 is printed, there will be text explaining this on the page which shows all of the various youth religious emblems.
It sounds like if you earned your Personal Progress or Gospel in Action/Faith in God award as a youth, you can, if you would like, wear the square knot representing religious award earned as a youth on your uniform. That's the silver knot with a purple background.
Don't forget either about the religious knot you can earn as an adult leader. The requirements can be found here. If your bishop doesn't know about this award, make him aware. There are probably many deserving leaders in your ward.