I wouldn't stress too much over it. I bought a 123 years ago that needed spacers and didn't have them. There was an annoying clunk sometimes from the rear when the axle moved. At the time I didn't know what was causing the clunk but after about a year I decided to investigate. I could replicate the clunk by grabbing the half shaft and moving it back and forth with the sound coming from the differential.
I removed the diff cover, pushed the axle all the way into the diff and measured the distance between the axle retaining clip and the splined housing. Ordered ones to stack to the thickness measured and it was done.
I contemplated fabrication, but the shims were cheap from the dealer. The only downside is that for a daily driver the diff cover has to come off to measure, and then again to install the shims.

__________________
1985 300 TD 448K
1984 300 TD 278K

1983 240D euro 240k
1994 f-250 idi turbo 330K
1986 f-350 IDI
1987 F-350 IDI

1985 JD 1050 4wd
1965 IH 3660