Joined: Jan 2010
Posts: 9,831
Likes: 1,809
From: Northern California
Bikes: Cheltenham-Pedersen racer, Boulder F/S Paris-Roubaix, Varsity racer, '52 Christophe, '62 Continental, '92 Merckx, '75 Limongi, '76 Presto, '72 Gitane SC, '71 Schwinn SS, etc.
You'll need to either peruse old catalogs for pictures and spec's, OR simply find the tiny, two-digit letter code on any of the Shimano parts.
I'm guessing early-90's vintage. The first digit/letter of the code is the year, 1991 would be letter P for example, 1992 would Q.
The codes are on the rear of each crankarm, and on the back side of each derailer.