Yep, I reproduced the stamp off my coil as well, it took me 4 times to "roll it" correctly, was a pain because I had to re-blast and paint the coil each time I failed, but patients got me what I wanted and it came out great in the end. I ended up having good success in the end by using a 2 x 4 and mounting the stamp the correct height on the 2 x 4 off the base of the table, and then just rolled the coil on the table leaving the 2 x 4 in position. Tried a few time using the stamp itself and that was a complete fail each time I tried, too shaky.
Jim, good idea on doing the date separately, I think there was a discussion on one of the threads about how there was a possibility it was stamped separately anyway which is why some seem to look a little different or distorted differently from the rest of the stamp.
Good luck Hipo giddyup
Jason