I stumbled across the website "55project.com" which has a significant collection of information on the Lyman 55 powder measure. Plenty of photographs, design details, catalogs, dating information.
Thanks for the info, my wife got me one a while back it is like new condition. The paperwork in the box said 1957 according to that site it is correct. Orange with the threaded hopper, works great, the quality back in the day compared to today what a difference. The price in 1957 16.00 she got it from e-bay for 35.00
I absolutely love my 55. I got a newer version and it meters everything I have well, and gives me some of the most consistent drops of any I've tried. I just wish it was progressive capable.