I pulled a drive shaft out of the parts pile for my 65 Mustang. I used a 6' section of 4" PVC pipe and capped one end, dropped in the drive shaft and 1.5 gal. of well used Evapo-Rust. Left it for 24 hrs., pulled out the shaft and noticed very little rust gone but traces of paint markings. Threw out the old Evapo-Rust and put in 1.5 gal. of new Evapo-rust and left the shaft in for another 24 hrs. Pulled it out totally rust free and with very clear paint marking stripes and yellow numbers. I dabbed the drive shaft dry as the paint was very soft and would wipe off. The paint colors of the codes were very clear. I'm not doing a concours restoration but I'm going to clear coat the shaft with a matte finish to preserve a piece of Ford history.
I had glass beaded a drive shaft a few years back and never saw any paint markings. I suspect the glass cleaned off the paint before it even became visible.
Thought you guys would like to know what I uncovered.

 

Similar situation with this early toploader I have. Just washed it off at the car wash. Not sure what I'll do with it. More markings on the other side as well.

 

Why don't you bring it down to the Kansas Speedway next weekend. They have a swap meet on the infield on Friday and Saturday. This is their first time for a meet and it has the potential of becoming an excellent meet especially since Wichita's February indoor meet is coming to an end next year.

 

Love to see some pics of the driveshaft