I have been watching some real cheap 1950s horror movies from way back then.
I noticed the revolvers they used went Bang but no flash or gas exited the barrel. This told me the BANG was dubbed in using guns without blanks or any ammo. A true Cold Gun.
I have no idea what they used to use but I watched interviews with Dean Cain and John Schneider on YouTube and true prop guns are rubber. Replicas for historicals are real guns.