I found another box of UMC 30 Mauser cartridges on clips and it is marked slightly differently than the other that I have. I don’t know if these boxes can be dated “older-younger” etc. but here are the photos. The clips and headstamp on the cartridges are identical.
The tops are not different -
But the sides are -
As well as the size of the print on the ends -
and bottom -