1) If you are shooting because you want to be the absolutely fastest shooter and go home with all the prize money, get two matched gun. They will balance the same and present the same sight picture. It will shave 10th's of seconds of your 13 second stage time. (That's not me)
2) If you read about the real "Old West", in the cartridge era, most folks carried one handgun. If a lawman or bandito, carried two, one was a strong side gun, the other was a short barrel "belly" gun or pocket pistol for back-up. As Short Knife commented, you are more historically correct carrying in this manner.
Pancho "Bat-Crap Crazy" Peacemaker.
P.S.: Last Saturday's match I was carrying a 6.5" S&W Russian on my strong side and a 2" Colt SAA Sheriff's model on a cross draw.