.45 Colt = .45 Long Colt
.45 S&W = .45 Schofield = .45 S&W Schofield (shorter than the .45 Colt)
Like said above, the .45 S&W can be fired in a revolver chambered for the .45 Colt but not the other way around. (like it top break S&W revolvers chambered in .45 S&W)
As for buying ammo, any factory .45 Colt ammo will be perfectly fine in your revolvers. If you decide to reload you can use any published .45 Colt load data other than load data specifically designated for Ruger, Freedom Arms, T/C Contender only. AND, the Ruger data can't be fired in all Ruger revolvers. It can be fired in Ruger Blackhawks and original Vaquero revolvers but not New Vaqueros popular with the Cowboy Action crowd.