In California, the personalized plate belongs to the person that requested it NOT to the car it's on. You can only transfer the personalized plate if you fill out a transfer form for the plate in addition to the normal paperwork.
So, If you still have a personalized plate, you can put it on your other 914 (or any car) or transfer it to anyone that wants that plate.
The exception is putting a "69" in the verbage. DMV will only allow "69" on a 1969 vehicle. This is due to the sexual connotation of 69.
I had
"69 BUZZ" on my 1969 Dodge Super Bee and transferred it to my 1969 Porsche 911. I still own the rights to 69 BUZZ even though I do not own a 1969 car any longer. I did have to write a statement of fact to the DMV to get the plate originally since they are idiots and thought my design was sexual and drug related. Fuching morons!
Bottom line, it you once had a personalized plate, most likely you still own the rights to it even if it has been out of the system.
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