If it is a toyota diff, it will have the diff (transaxle) code on the compliance plate. I don't think any of the BW diffs are noted on the compliance plates. If you tell us what the code is, we can help you a bit more with the strength.
I think Toyota diffs have the bolts on the front of the diff and BW have them on the back.
If it is a BW diff, getting a LSD for it shouldn't be too much of a problem.