Don't usually pick up clear Hemi 42's but this one was a little different, it's the one on the left and it has the following embossing Front HEMINGRAY-42 Back MADE IN U.S.A 15 The one on the right is for comparison and has the following embossing Front HEMINGRAY-42 8 = 10 DOTS (1948 production date Back MADE IN U.S.A. 20 B Note the difference in size. Now for the question: if the 15 is the mold number then what's the production date ??????