Leeroy
I have 888866 this plate was on my Mustang and I transferred it easily across to the Cobra. Think the charge was $80 to do this.
The Registration office saw the 888866 as a vanity plate which is the same price as the word plates such as EVLCOB. They were about $290 when I got mine.
All plate 'words' must be approved by the registration office and you just go in as you suggested with a long list and the 'helpful' staff will check each one out.
You can reserve the plate and have it held at the registration office. Once you have the plate in your hands and on a car, you keep it and ring them when you want to activate the plate and put it on another car.
Make sense?
I would go to a local registration office rather than the central one. You will find there is less of a line and the staff are a little 'more' helpful.
A few of us are over at Doug's this Saturday. Its an easier trip on the weekend, may see you.
Cheers
Bernie