I own a 48 Woodie and also have body numbers stamped on the firewall. According to the Sorenson book Famous Ford Woodies, the number, 39633, indicates the car was a very early production model since 1948 models started with 39487. Based on the production of the glass which decodes to Sept. or Oct. date codes, the body number and timeline appear accurate. Also, the car has the original "Patent" tag on the firewall with a small open area in the lower right hand corner with the letters LB stamped in the tag. This indicates that the car was produced in Long Beach, CA.