Thank you for the pictures.
In addition to what WIChix told you (
especially about using yarn to polish presser & needle bar
)
There are a couple of "stickies" here in the vintage forum about cleaning machines -
How to Clean Up and use a vintage sewing machine - videos by Muv and Fav and
Cleaning and repairing the Shellac clear coat on Vintage sewing machine heads
I believe you actually have a 127 machine with a serial number of G7303950, which was one of 50,000 allotted August 28, 1919. It is really hard to tell as "G" serial numbers used different fonts over the years. A few things that indicate the 127 would be the high bobbin winder, the tension assembly and the shuttle ejector.
I also think that you have one of the style 7 "puzzle box" based on the ruffler with number "12" on it. The ruffler and tucker for the style 7 are shown at
http://needlebar.org/main/puzzles/style7/index.html http://needlebar.org/main/puzzles/index.html shows the different attachment boxes.
Manuals for the 127 can be found at
https://www.sil.si.edu/DigitalCollec.../NMAHTEX/2678/
https://www.sil.si.edu/DigitalCollec.../NMAHTEX/0650/
http://ismacs.net/singer_sewing_mach...ls/127-128.pdf
You can get the plate, spool pin and belt from sew-classic. I don't know the exact ones you need. I haven't actually called or emailed, but have heard that she is very helpful to communicate with. I have been pleased with what I have ordered from there.
https://shop.sew-classic.com/Plates-...Plates_c14.htm
https://shop.sew-classic.com/Spool-P...-Felts_c15.htm
https://shop.sew-classic.com/Belts_c3.htm
I noticed you may be missing the front inspection plate. I don't think you really need it. Since it is a flat piece of metal, probably it wouldn't be hard to fashion one if there is a screw that will fit.
I didn't see a buttonholer, but did see the neat buttonhole cutter and the neat wrench.
Have fun with your "new to you" sewing machine.
Janey - Neat people never make the exciting discoveries I do.