I have a class 4/5 hitch from a '95 available if anyone is interested. It was fitted to my E150 Quigley but because it's complete overkill for a 150 I replaced it with a bumper mount hitch.
THats interesting. I pulled one off an 07 to fit my 99 and it most definitely did not bolt up.
The plot thickens... Aparently 1999 is an odd year. None of the hitch manufacturers show a fitment for A 1999 e350. The Curt 14053 shows to fit a 1999 e250, arent those the same frames?