BTW- nothing to do with the Singer model 15, and not a "clone" in any shape or form.
Interesting that it takes a 15x1 needle, also known as the 705H, or what Singer calls 2020. The Standard machines I have take a different size, Boye 6 (BTW, the 15x1 is also a BOYE 16 needle).
Please post pictures of the attachments - will be interesting to see if they are the ones for Standard machines. Often in the last 100 years, the attachments got switched around and what is now with the machine may not be what came with it long ago.