MAYBE, MAYBE NOT
It depends on if they are the same axle or not. 2500 auto trucks use a Dana 70. 2500 manual trans trucks and ALL 3500 trucks use a Dana 80. If they are the same axle, the differential carriers will interchange from '94-'01 (I have Okie-Go's '01 LSD in my '94) and probably an '02.
Like powerwagon stated, you just put your "old" ring gear on the "new" carrier and check the backlash. You might put new bearings on it while you're at it and you might need a carrier bearing shim kit from Dodge. They're not cheap but it could take a few days to get so have one on hand. You should be able to return it if you don't open it.