I found this nifty little pinking tool at a junk shop the other day for $8.
While it looks very similar to the ones used on 18th century scalloped fabric trim it's definitely not as old as that, and is almost certainly meant for leather. Searching "T Dixon & sons" brings up a lot of leather tools, and I found one website that says the company started in 1843 and went out of business fairly recently. They didn't list any source, but the first result on google books is an 1892 ad in a saddlery trade journal that says "Estab. 1843" at the top. The ad also says "William Dixon & Son (Late of the Firm of T. Dixon & Sons)", so I think mine is from before 1892. In any case it certainly looks hand forged. I haven't looked very hard for more information yet.
I tried sharpening it with my narrowest metal file, and then with a folded bit of fine sandpaper, and it's better than it was but still pretty dull. It takes quite a few good whacks to get through even my thin glove leather scraps. I can't use my oilstone at all on such an odd shape and such tiny angles, alas, but there must be some way to sharpen it.