Lock washers on the rear transmission bearing retainer

[wrndln]

When I dismantled the transmission I am now rebuilding, there were lock washers used on the four bolts that fasten the rear bearing retainer to the transmission. The washers were Ford lock washers that have the serrations on them, not modern lock washers someone decided to install. The bolts have safety wire to keep them from coming loose. There is a slight concern that if the bolts go in too far they could possibly interfere with the cluster gear, thus the lock washers. In Les Andrews volume 1 (picture below), it says nothing about lock washers. I have heard there are errors in Les' book, so I thought I would check here to see what Fordbarn people think. It may not make any difference either way, I just want to do it the way Ford did it.

Added note: All the bolts used on the transmission had lock washers on them.
Rusty Nelson