An idea - Try to find out who is making the pins - As limited a use that there is for them I would imagine that there are only one or two making pins for all makes of old vehicles
Figure out what size you need and contact the manufactures and see if they make one that will fit your need
The other way is get a small machine shop to make up a set and get then hardened to the right spec.
1948 Ford F1 Panel
1952 Ford F2x2 (Non-Stock Flat 6)
2016 GMC Canyon
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