I have 2 Steptoe shapers, a 16" and a 20". The 16" I bought from my high school machine shop while I was in the 12th grade.

That was 35 years ago. The 20" I bought recently.
I do not know the age of them, but thiink the 16" is from the teens. Our high school had gotten it from government surplus in the 1960's. It was originally flat belt driven, but had been converted to motor drive and V-belts. Serial no. 7, Lot no. 282 is stamped on top of the ram.
The 20" is newer, but still has its countershaft. Serial no. 731, Lot no. 341. It had been used in a lineshaft shop in Madison, Wisconsin before I got it and was never converted to individual drive.
I do not know if Steptoe used a Lot no. when numbering their shapers or if both these shapers were originally government bought and the Lot no. was used by them?
Mark