Does anyone have any information on this "vintage" strop.

Given to me by a family member who believes it's from 1900s. But I honestly don't know. No brand or make markings at all

WOW! I don't have any information for you, but it is beautiful!

any hallmarks on it?

not a single hall mark. theres a tiny tiny number scratched into it saying "3658 km/s" but its insanely small and clearly been done ages after production.

I have one exactly the same somewhere, which I bought at a swap meet. I've always felt it dated from 1910-1920ish, and was probably made in England.