Underwood Typewriter Dating

I spent the best part of eight hours yesterday working on restoring an Underwood standard. I've had the machine for about 10 years now - it has had a very chequered life, even in that time. I've never been able to completely satisfy myself whether it is a Model 5 or 6 (it came to me with no decals at all). And the serial number of 4117741-10 suggests a 6 with a 10-inch carriage and 1932 as the year of production. But yesterday, while taking it completely apart and cleaning it up, I was surprised to notice this date on a metal clasp at one end of the padded typebar rest arc. It clearly states August 18, 1903. Has anyone come across one of these date stamps on a typewriter part before? It's hard to believe a part made in 1903 was still being using on Underwoods almost 30 years later.  Anyway, I'm ploughing on with the restoration today and still weighing up whether to apply another paint job - by my estimation that would be at least its fifth repaint - or leaving it naked. Paint is the preferred option, but we'll see. I'd say that without a doubt it has been "remodelled" at some point; it started out as black, then had a crinkle grey finish and then a light green shade. Watch this space ...
PS: Ted Munk sussed it very quickly. It's the patent date for the Underwood standard typebasket, patented by Louis Myers (later co-founder of Royal). Thank you Ted.