I get the 1975 (Terry's birth-year) reference, but really, that's too high for a TOS Connie (25 less than the Excelsior @ 2000). 1795 would have made more sense. At least to those who still think Registries are sequencial.
Maybe the New Jersey was built from left over scraps at the end of the TOS Connie refit process specifically as a museum piece?
I've always felt like the NCC (Naval Construction Contract) numbers in Trek were never meant to be sequential through a class of ships, but fell in the order that ships of various classes were ordered up. That would account for jumbled numbers. Say you have half a dozen ship classes, but you are only going to order 12 Connies, and 1999 is the total number of ships in all six classes. Depending on the order of their construction / commissioning, their NCC numbers can be all over the place.
For this reason alone, it made sense that they re-registered a previously built starship 1701-A in order to honor Kirk and rename her Enterprise. It did NOT make sense to go with the bloody B,C,D,E and so on registry numbers.