Oh! Okay...I get it... So it really doesn't have that much to do with the "gun" itself, but more actually as a sort of "status symbol" as it were! Thanks.Basically, think of the BBQ as a social\political event and then getting dressed up for it. Your BBQ gun is what you took to the social. And in some cases, it was a shoot and a show and tell...another way to enjoy and share guns.
Also, in the Southwest and especially Texas BBQ's are social occasions and also frequently used as a way to raise campaign funds for county sheriff's, constables and judges, all elected officials. Hence the name BBQ gun for wearing your favorite gussied up sidearm for evereyone to see and admire. The fancier the firearm and leather the more succesful the wearer is considered, much like an east coast buisness man wearing a Rolex instead of a Timex to a buisness or social ocasion. They are both a symbol of success and prosperity. By the way they need not be a revolver or have the steerhead but pearl , stag or ivory are considered to be required for grips, now all fancy grips are accepted and appreciated.