Yep, Singer Model 15K, 1 of 75,000 allotted 4-4-41.
Low shank feet and attachments
Class 15 x 1 needles
Class 15 metal bobbins
Good machine for just about anything.
Use sewing machine oil and cotton balls or soft flannel cloth to clean it with.
Suggest Tri-Flow oil if you can get it where you're at, it's better than normal sewing machine oil. At any rate, since it's been setting for so long, clean it good inside and out ( under the needle plate, slide plate, inspection cover, under the bottom and oil oil oil it.
Clean and oil the treadle contact points and bearing too.
When putting on a new belt pre-stretch it if you can, ( I can't ) or put it on a bit tight, it will stretch.
Strongly suggest putting in a good supply of needles, they wear out, can be bent or broken, and are cheap.
Bobbins too.
Joe