Is this the number stamped into the name badge on the headtube? It would appear more likely to be the serial number. The date code stamping is about 1/3 the size of the serial number stamping. I'm unsure of any method to identify non-Schwinn built Schwinns by the serial number, except possibly for Giant built bikes. Whether this is true or not, I've never been able to ascertain, but I was told that Giant built Schwinns would add a date code stamped into the dropout opposite the dropout containing the serial number. If I recall correctly, the date code was a four digit number preceded by the letter G. I don't know what format the Giant date code was supposed to follow as our shop always used the Schwinn code from the name badge for our records.
Greg Groth
> Message: 4
> From: "Garrison Hilliard" <garrison@efn.org>
> Reply-To: garrison@efn.org
> To: "Greg Groth" <ggroth@telocity.com>,
> <classicrendezvous@bikelist.org>
> Date: Sat, 8 Sep 2001 15:19:16 -800
> Subject: Re: [CR]Re: Schwinn Voyager
>
> This is a 4 digit number, 3 digit julian date
> >with 1 digit for the year. For example my Letour II (made in Japan) is
> >stamped 3506, meaning it was manufactured on the 350th day of 1976 (you
have
>
> >to have a little insight to pick the model year) making mine a '77 most
> >likely. I'm not sure when they started this practice, but have seen it
used
>
> >on their bikes from the mid 70s to present day.
>
> Okee-dokee, try this... Schwinn Traveler number sf611386