If that's not an S2, I'll eat it. I poked around the net and couldn't find a picture to verify it, but there are various S2 owner sites out there and sending a picture to one of them might solve it for you.
The overall lines, the perforated rail around the deck
, the shape of the transom, etc. all make me think it's an S2, made in Holland
S2 used do like to use a lot of sort of a lightweight carpet/frabric glued all over the interiors of their boats. If you have a bunch of that, it could be another indicator that it's an S2.