Hi Bill,
MY 53 TD, Yeah that was a cool vanity plate. Unfortunately, by the time I started driving that car my father did not want to pay for the plates anymore and I was in college so I just got regular state issue plates. So as far I know, the # should be up for grabs unless maybe they hold it for a time or if someone else already took it.
Actually while writing this message I checked the NYS DMV and it is available. So go for it. Hope you enjoy it!
Geoff