I have noticed crinkle finish machines from the 40s and well into the 50s, and according to ismacs an early Kenmore / White model had the crinkle finish by 1933. That's roughly the time frame this type of finish was common. It was popular enough to be used when older machines were refurbished and that's part of the reason why some suspect yours might be.
If you can detect traces of previous decals under the crinkle finish it's not the original. You can usually find traces of the original finish by taking a closer look behind the faceplate and under the base, the overlapping of paint and bare cast iron usually reveals something. If you see anything black it's probably shellac; some primers can be grey of course. Yours looks very nice either original or refurbished. Refinished machines were probably never sanded down to bare metal.
Straight stitchers were made up until the early 1960s, as well as vibrating shuttle models (long bobbin) model. (15 clones for even longer) They could be very simple with clasic looks like yours, and with out other factors narrowing down the time frame it's hard to rule out anything for sure.
Last edited by Mickey2; 02-22-2018 at 01:44 AM.