....off topic.... wellcome to lost, check out the carolina lost sections or
www.coastalcarolinaoffroad.com to hook up with some guys to wheel with in the area. Its always nice to have a buddy out there when your wheeling (i learned the hardway). Theres also some liberty nuts out here that can help you with any problems your having. Theres even a shop down here than can do a kick stupid SFA swap on your rig for around $6000, not including tires.
....on topic.... it is a silly thing, but it is pretty much the same dif, except it in ifs form and made out of aluminium. Some lockers that fit the d30 - ARB, DTT, also fit the d30a. I have yet to see a piece of chrysler literature that has d30a in regards to our differential. Also, are you sure you have a locker in the front? Or are you talking about the front & rear driveshaft lock that takes place when your in 4lo or 4hi?
Also, I would recomend even if you have a aftermarket rear dif. cover with a drainplug to still take the cover off and inspect the inside now and then to make sure all is well & to get any metal particles out that may be floating around in there.
and for the 8.25 "anti-spin" differential is whats known as trac-lock or "trash-lock" as it has become known as in the jeep community
its a limited slip that helps to reduce spin, but doesn't work that good imo. The 8.25 has a larger variety of lockers from around $300+
again, welcome to lost! hope to see you on a trail soon.