Ron, I had a pair of British guns (A&N, made by Webley & Scott) that were less than an ounce apart. Have had a couple Spanish pairs, one of which was closer to 2 ounces apart. As Rocketman indicates, I could not tell--without looking at the number on the gun--whether I had AyA #1 or #2 in my hands.
From the difference in bore diameters on your guns, post-Briley work, looks like they might be pretty close in weight if you were to have Briley bore out the tighter pair to match the lighter/backbored pair.