Brian,
I'd take an educated guess that the binnacles would be interchangeable I've never actually tried though, but agree with Neil that it just won't look right for a starting point.
I would also agree that the most likely fault is the oil sender itself rather than the gauge, checked the wire is attached to the sender? Or tried shorting the wire that plugs onto the sender to see if the needle in the binnacle moves, that will at least prove what is faulty.
If its brown with round moulded sections round the speedo and rev counter then its S1 or early S2, if its black and there is a single rectangle of perspex over the front then its S2/FL onwards.
Lets us know...