I'm updating this thread in case there are any lurkers or for future reference. Anyway, it's not just the followers that changed on the new G31 mags. They partially redesigned the magazine body and added two ribs to the inside, one on each side that go from the feed lips down around 1.5 inches. Essentially the area where the magazine is tapered. I'm assuming this is keeping the bottle necked cartridges in better alignment as they go from a staggered row to a single row at the feed lips. The new follower has slots on either side to account for the ribs in the mag body. I test fired yesterday, and the new design works great with 357 Sig Gold Dot 54234. The spring pressure is much stronger, and there's no nosediving of the bullet as it's raised to the feed lips. The #5 followers alone are not an improvement, as I tried them in my older G31 magazines. It's surprising Glock made the redesign this late in the game. 357 Sig isn't a popular caliber, so they could have left it alone. I'm thankful they did, since now I have more faith in my 15rd mags. The part number on the back of the mags is 4363-05, and the box is MF31015.
Gold Dot 357 Sig in G31 and G32
It's been a few years, but I'm hopeful Glock finally got the 357 Sig Gold Dot feeding issue resolved. I bought a new Glock 32 a couple weeks ago, and noticed the magazines had the number 5 follower. I didn't know they progressed beyond the number 3's I already owned. So I loaded them with some Gold Dots, and they cycled great when ejecting with my thumb. Then I shot about 6 full mags worth of Gold Dots. There wasn't any bullet nosediving like I previously experienced. So I ordered some 15 round G31 mags online, hoping they were the new followers. Turns out they have the #5 followers too. I hand cycled Gold Dots through the two new magazines, and there was no nosediving at all. There was good spring pressure on every round when I cycled them by hand. That was not the case with all my old 13 and 15rd mags with the #3 followers. I'll test fire the new mags sometime this week, but I think they'll function great based on what I've seen so far. This had been pretty frustrating for me, since I had a little stash of Gold Dots but didn't fully trust them in my G31 and G32.
