That looks like a similar vintage to my Singer 522 - same overall body shape but with more bells and whistles. From experience, although I've never used it on leather I do know that it had to be coaxed to stitch over a hem that included a flat fell seam in denim (at least nine layers when you add them up) so unless the leather is fairly fine, I'd be careful. It definitely won't handle saddlery-weight stuff, of course.
I'd put a bit of machine oil on all the usual spots and run it without any fabric first, to make sure it's still working. Assuming it is, get a leather needle and some leather scraps and give it a try. The worst that can happen is that it refuses to feed the leather.