It looks like a 92 Timberline or lower. But those brake bosses are not for a u brake which would make it later than 92. However they don't look original to me, So I still think it's a 92. The reason I'm fixed on 92 is the gearcable stops on the down tube are on the sides directly opposite each other rather than a bit further round towards the underside of the tube. I'm sure '92 was the only year they did that. Earlier Timberlines and lower took a 1" steerer (yours looks 1 1/8", yes?). 91 tequesta had 1 1/8" but it had removable seat post clamp and a 73mm bb shell (Yours is 68mm yes?). 92' Tequesta the same seat clamp as your frame but had vertical dropouts and 73mm bb shell. The 92 Timberline looks just like your frame, same dropouts, gearcable stops, 68mm bb shell, 1 1/8" headtube the only difference being the brake bosses and it also has bottle bosses on the seat tube. Could be your doesnt have them because it's a small frame.