I don't know our axles, I know gears/lockers from my jeep days (Ive done a few ARB Locker Installs, lunchbox lockers, and Detroit Locker installs). Gear ratio only matters to a carrier swap if there is a carrier break. That means that when you change gears in that axle, gears below a certain ratio uses 1 design carrier, and gears above use a 2nd design carrier. Basically it is how close the ring gear mounting surface (on the carrier) is to the pinion gear (left and right on the carrier). To make up for carrier breaks, some ring and pinion manufactures developed "Thick cut" gears, which make up for the additional spacing allowing you to keep your current carrier across the axle ratio break.
If an axle doesn't have a carrier break, there is only one carrier design (Open/Limited Slip/Locker/Spool), so just order the carrier for the correct axle. From what I can find (with no gear/carrier install knowledge on my truck), I only see one carrier for our rams. This would mean, even if they ask, it wouldn't matter what ratio you tell them.