Yes I can`t understand why they would scratch the number in when they was a serial plate, likely will never have a answer.
The farm saw had cheaper spark controler and also cheaper drive and maybe other things, my dad in around 1980 traded a ICL pioneer for a Farmsaw and it seemed okay and then he traded it for a new P39 Plus which he liked better, I did not like the red colour but that is just me. I purchased my Pioneer Partner P42 which I said before came from the Pioneer testing dept and it was like twice the saw cutting hardwood compared to the Farmsaw. The Farmsaw was like $50 cheaper than a P41 here in Ontario and my dad would not spend the extra money, a dollar was a real dollar then. Les