FWIW, the 19# injectors I've been running off of a '95 4.6L T-Bird didn't require different pigtails - they just plugged right in. The 24# injectors should be the same deal for the early 90's 4.6's, probably up until they changed a bunch of things on the 4.6 across the board in '96 ... y'know, plastic intake manifold, OBD-II emissions, etc. The earlier 4.6's in the MN12's (T-Bird/Cougar) and Panthers (Crown Vic/Grand Monkey/Town Car) should be the earlier style of connector, but the newer injector outlet type (4-hole disc instead of single pintle design).
Then again, come to think of it, I believe that even the newer Crown Vic 4.6's use the same type of injector pigtails as the older ones, IIRC ... I'll hafta take a peek at some engine bay pics and double-check that...