That is very helpful. I put some graphite on the end of my finger and rubbed it along all the lettering and logos (slow night here). The round Kelsey Hayes logo is easier to read now and it definitely says only 'Made in USA" inside the logo. The round funny looking insignia to the left has a reverse image 'P' and what appears to be half of a 3 but more like a soft 8. That may be the Philadelphia designation you mentioned. What did show up which was not visible before is a '3' to the right of the upside down '7'. It is smaller than the 7 and is at a 90 degree rotation from the 7. Looks like it could have been on the same die punch and may be the 3 referencing Philly.
The strange thing is the K designation in the size which was used for the '64 model year. I would have thought it would have been a J for '63.(?)
The strange thing is the K designation in the size which was used for the '64 model year. I would have thought it would have been a J for '63.(?)