and now I'll add somthign more constructive, any more pictures.
there where Imported (at least at the later stage, no idea of the early part of Rocky Mountain)
Japan import, so probably Toyo ?
Serial may be a Toyo serial number and someone might know what they mean
Things like groupsets may also help.
If that's 'cobalt blue' thougj, it may be 1987, have M531 rear mech
and AT50 brake setup.