Rear Axle question

[DPF]

Hello all, I have a 79 that had 55k miles on it when we purchased it from a friend that had it for just a few weeks. He purchased it from the original owner, an older woman. The posi clutches started to slip, and I added some of the additive needed in a posi. It got bad enough that being a retired mechanic, I removed the rear and opened it up. The first owner gave my friend all the receipts for all work done on the car, and no paper work indicated the rear had been worked on. The strange part of this is that the bearing caps were already match marked to the respective sides of the case they were installed on. All the diffs I have had apart, I had to match mark the cases and bearing caps on most all of them. I wouldn't think the factory used punch marks to indicate the sides the caps were machined for. I would imagine the are just tagged with something insted of taking the time to punch mark the caps and case. Also one of the bolts that held the housing to the crossmember had some masking tape on it, and the pinion flange was not match marked to the pinion shaft. Any ideas?

 

[GTR1999]

Sounds like someone was in there before. Change a gear ratio? If the same pinion nut was going to be re-used when replacing a pinion seal you would expect a mark on the nut and pinion but if the gear set was replaced then you would use a new nut. The yokes are known to wear in the late 70's cars maybe they were replaced- what do you have for endplay in them?