Later Schwinn serial numbers / years made. Bicycles from Japan made in the 70’s have a production month letter in either the first or second position and a production year number in the other (first or second) position. Examples J677123 = September, 1976, 6J77123 = September, 1976.
Want to find out if your Homegrown was made by the mythical magical elves at Yeti? Click on, my friend. This page lists all Homegrown models, and you can sort by multiple options at once. If you sort on a color a bike will be included even if it's not pictured in the catalogs in that color.
Click the link icon on mouse-over of the bike image to view the detailed specifications and related models. Click the magnifying glass icon to enlarge the picture. The info on manufacturer for each frame was corroborated by Schwinn's former engineering manager, the engineer in charge of design and sourcing for Schwinn Homegrowns, and the product manager for the Homegrown line.
Hopefully this eliminates some of the confusion about who made what models. 37230 reads.