Yes, Orange Micro "Grappler" IS almost certainly a printer interface.
Orange Micro was heavily involved with printers and interfaces for them in
the 1980s.
It probably won't help you any, but I'm pretty sure that there was one of
those boards in one of the Apples that I gave away a year ago, and there
is probably documentation for it in the stuff that Sellam got from me.
(Yes, I understand your workshop being crowded. I recently had to give up
2000 sq ft of storage, and had to get rid of lots of stuff, even magazines
and some books.)
--
Grumpy Ol' Fred cisin(a)xenosoft.com