You might as well get some more barrels fitted to your reciever while you're there. It do take a while (like all summer). Then they can treat your replacement barrel as one of the fittings. I'd send them a note specifying the kind of rifling you want (if they have it). BTW, they have a 15 dollar fitting charge on top of the 89 dollars per barrel, and they have some barrels that cost more. Watch out for their twists (check before you order)! They tried to sell me a 44 mag with 1 in 38" twist!
I've always thought that industry standard for 45 caliber was .450 bore, .458" groove. Why else do they make all of the ammo .458? .002" tolerance? What else besides a tractor tire has that much slop? Tell them gun barrels are measured in tenths, not meters! If it aint microgroove, then ask them what else has .002" deep rifling (besides a worn out barrel)! Pardon my ravings, I'd probly be a scosh piffed if it were mine!