In the 80s, Nashbar sold complete bikes under their own name. Before this period, they sold some framesets but didn't come with a Nashbar decal. After the 80s, they continued to offer complete bikes into the 90s, but also sold frames separately. But this wasn't one of them.
Their company name went from Bike Warehouse, to Bike Nashbar. Finally changing to Nashbar.com.
(probably when they got acquired by Performance Bike)
Try soaking the rusted parts in molasses. There's is thread here on the procedure.