Looks like you have a tractor 8 judging by the little wheels, 11's had 16-6.50x8's on the back
Don't think greenfield ever did anything like that, they weren't the best record keepers by any means. If lewis reinhold ever surfaced again he might have half an idea.
From all the pics i've seen you're anniversaries are all original, as horrible to work on as they were, they weren't greenfields finest models.
Its not terribly hard to tell if something has been modified, as it generally won't work properly!
