You should be able to dechiper the year from the stampings on the BB. It should have a prefix of MO, plus a letter. MO-B would be 1937, they used this alphabetical year through N in 1949. They skipped O and went with P for 1950. Some bikes, like those made for Sears through the mid 50s were stamped MOS-X, with X being the variable year letter. -Adam