Help dating a primer tin

My apologies to anyone who was bidding against me today on Gunbroker ;)

I got this brick of UMC No.5 Primers for paper shot shells. The box is there but not in good shape. The tins inside however, are awesome.

My question is this: can anyone give me an approximate date of when UMC stopped putting primers into tins and switched to the flat boxes with wood inserts?

thanks in advance.

I have those raised letter UMC tins in; 1, 11/2, 2, 21/2, 3, 5, 6, 61/2, 7, 71/2, & 81/2. So found in a wide range of primer types & thus hard to date.

However I have 3@ U.M.C. & C.Co. tins, & all of those have the raised lettering on the lids, so perhaps U.M.C.Co. just continued the practice?

Edited once to add:
I think the tins with glued-on paper labels likely came next & then the lithographed or perhaps silk screened label variations, & then or perhaps with a time overlap, the sleeve / tray boxes. All this is a slighly educated guess, perhaps a look through old catalogs might help yield an answer?

Thanks Pete! I knew you would bring some history to it!