I agree with THEOTHERGUY regarding the manufacturer of SR bicycles. The ads introducing the line, first starting appearing in 1979.

In the early 1990s, SR manufactured another bicycle brand called Prism, which had a bonded aluminum frame.

The source for the Mexican manufacture rumour probably lies with the name of the SR's US distributor, Windsor Enterprises Inc. To the best of my knowledge, this company had nothing to do with the Windsor bicycles, which were distributed through West Coast Cycle or Alpha Cycle and Supply, depending on the year.

However, there is some evidence to support the story of some design work for SR bicycles being performed in San Diego. The offices for Windsor Enterprises Inc. were at one time located in Chula Vista, just outside San Diego.