Will this fit my truck

Why so much controversy over pinion spline size? 2009 tacoma 4x4 base model, narrowed it down with my code being A04A to being an open 8.4 rear diff with the 3.7 gearing, please correct me if im wrong (this is the info I found online). Will this part fit, autozone, yukon website, extremeterrain, and other websites all say it fits.
part number - T34030 (ordered from yukon)
https://www.extremeterrain.com/yukon-gear-tacoma-differential-end-yoke-yy-t34030.html
Don't want the part to arrive and my truck not be a 30 spline, any help is very appreciated.
Billy

 

If I could drop the driveshaft and count it I would, hoping I can just find this info, worst case ill take it to a buddys shop an hour away and do it there.