20th Century brand treadle sewing machine

I inherited this treadle sewing machine from my grandmother almost 50 years ago. It is a 20th Century in an oak cabinet. The plate that covered the shuttle was lost during a move many years ago, but prior to that, it sewed perfectly. The last patent date on that plate was July 1912. And the serial # I found under that plate is 1078099. Also , there were no side drawers to my knowledge (my dad added those a few years ago). My grandmother purchased it in the 1940's in Shawnee, OK for her daughter.
I would like to purchase a manual and replace the cover plate so that it will be usable again, unfortunately i cannot find any listing of this brand, if anyone knows of it or another brand that the parts would be interchangeable, I would really appreciate it. Thanks.