The decal style is consistent with 1985, not 1975. The stamped dropouts and lack of brazed-on features with the exception of the two top tube cable tunnels and chain stay cable stop are indicative of a entry level model. It's definitely typical of mid-1980s, entry level Centurion models such as the Cavaletto and Signet, which used hi-tensile steel. I'm not aware of Miki having manufactured their own hi-tensile steel but have no reason to dispute it. The fork likely says Tange because it came form Tange's pre-fabricated fork facility. It was cheaper to buy complete forks from Tange, than for bicycle companies to manufacture them in-house. The best indicator to confirm hi-tensile steel is to measure the diameter of the seat post. Basic hi-tensile steels typically use 25.4-25.8 mm seat posts, while some lightweight hi-tensile steels use posts as large as 26.2 mm.

I'm not sure if that chain stay Novara decal is a model name or an aftermarket REI decal. I suspect the latter, as it does not have the dark blue outline to match the Centurion decal. The frame doesn't quite match a 1985 Signet, as it lacks the down tube cable stops for stem shifters. However, it's quite close to the 1984 Cavaletto, including the colour. It could be a non-catalogued or non-USA model. It's definitely been frankenbiked to an extent, based on the dual pivot brakeset. The crankset may be a replacement too. The Honor and Spirt derailleurs while more typical of 1975, were still available in the mid-1980s and were actually spec'd on the 1984 Cavaletto. That raises the possibility of a mis-stamp on the year indicator.

Selective photo assist...