S/N OA37416 points to January 1986.

Per T-Mar's database. Asian Serial Number Guide

MIYATA (Japan):

1985-1989: YFxxxxx, where N=1985, O = 1986,...S=1990.

Y indicates a numeric character designating the last digit of the year (i.e. 1 = 1971 or 1981, 2 = 1972 or 1982, etc.). With such codes, you have to determine the decade based on frame characteristics, components, etc.
F indicates an alpha character designating the fortnight (i.e. A= weeks 1-2, B=weeks 3-4,....Z = weeks 51-52)