Atlas 2 question

I'm buying an Atlas 2, and Advance Adapters ask me if my transmission output has 28 or 31 splines.
How can I know this? (Without taking out my actual BW1354, of course).

I have an Oct '94 4x4 XLT, 4.0L, 5 speed manual, 4 door, T-case BW1354 w/elect. shift

Thanks in advance, and excuse me for my English.

 

[Alfredo]

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