I've re-keyed many of these old locks myself, there's only 5 cuts or so-I use a Frisbee to keep the parts from disappearing, disassemble the lock, match up tumblers, re-assemble. There's even a how-to in the 63 truck shop manual. Bi-focals or magnifying glass may be required.
On the last glovebox lock I did, I simply pulled a couple tumblers out-any old GM/Briggs key will open it now. I'm not worried about security too much in that case-you could reach up behind & rip out the cardboard if you really wanted in there.
