How tight is the Pinion Yolk?

I removed a yolk from a spare diff and it was on there pretty good, I took a BFH and hit it several times from the backside (it was out of the car) and it came off.

It slips right onto the 489 case and bottoms in the splines but there is a little slop. I did not attempt to tighten this up yet but it has me worried that the splines are worn.

This is a 10 spline 489 case diff and it came with 4.30 gears and no yolk, my plan was to transfer the yolk over and tighten it up.

I bet it is more involved than I hoped. If I put it on and tighten it up to torque spec and the backlash is ok what could go wrong?

Go ahead, give it to me!