I own two of that pattern, neither marked "Stanley." One has the October 22, 1872 patent date on it - the Justus Traut patent on the split beam - and fractional increments marked on the beam. The other has neither of those, but is otherwise identical in appearance; both are rosewood.
I've never thought much about it; just been grateful to own them. The pins are pretty well worn out on the one, so it's on the sick list until I figure out how to redrill holes.
------
Later edit: although it is kind of odd, since Stanley was proud enough even of the low-end No. 61 to put their name on it.