The earlier Boot Hill 2nd edition box set mirrored the contemporary Holmes edition Dungeons & Dragons box set in its structure. They used a glued-sheet-on-paperboard box.
At some point, TSR switched to a box where the graphics were printed directly on the paperboard, used with TSR’s early-80s sets and beyond.
Some comparison photos follow. Note that TSR, in the transition period, did some mixing/matching of parts, based on available supplies I’d reckon. I’ve seen the early TSR dice in a later format box set, for example. And I’ve seen later print books in early boxes.
Early and later Boot Hill boxes
The early Boot Hill box also came with a pair of TSR’s early “Low Impact” dice. They were notoriously quick to wear, but are rare and popular with collectors now.
The early set had noticeably thicker counters.
EDIT June 28 2019: Another set arrived in the shop. More photos!