Throw Out Bearing Question

[1968C20]

Hello,

Was looking for some help I was having with a throw out bearing. I have a 1968 C20 that I am restoring. This is my first project so things are going along generally well, but of course with a few mistakes along the way. The drivetrain is a 383 with a 4 spd. stock tranny GM4 3901131. The 383 is a rebuild from a 1971 donor C20. Unfortunately when I put the motor in, I used the wrong throw out bearing- the bearing was too long and the clutch didn't work properly. With the pedal in, it seemed like everything was still spinning, the gears would just grind when I tried to engage it into first gear. I used the same size throw out bearing as the one from the donor truck. Thought that was the right thing to do, but come to find out, I guess I should have checked the bell housings as well as probably some other things....live and learn- the hard/exensive way
At any rate, the crank now has about 18 thousandths of end play. Took it back to the guy who did the machine work and the bottom end of the motor and he said the thrust bearing had about 10-12 thousandths worn off of it. Now for the question. Could this longer bearing have put extra pressure on the crank therefore causing that thrust bearing to wear? I can't quite wrap my brain around whether a too long throw out bearing would put more or less forward pressure on the crank. Thanks for your help!