Originally Posted by
markk900
That looks like a replacement rear derailleur (S001 instead of a 637 prestige) so I wouldn't rely on that for dating the bike.
Your eyes are sharper than mine! Thanks for the catch.
Originally Posted by
jj1091
If the downtube stripes are squared off it would be 1970-1974 (Type II), but with the angled ends it is between 1974 and 1976 (Type III).
I think there may be plenty of exceptions to that rule, or at least some overlap between the two decal types. My UO-8 seems to be 1972-73 based on component date codes, but it has angled ends on its downtube decal.
And to add another two cents to the gearing discussion, my UO-8 had 40-52 chainrings paired to a 14-26 five-speed freewheel.