No. They were most definitely D3 at the time, just like all the other SUNY university campuses. (Caveat, back in the days you are talking about, there was no D3. It was only D1 and D2.)
At one time, SUNY did not allow any of their institutions to play anything but D3, once D3 was created. And like I said, U. of Buffalo (as well as Albany and Binghamton) was in the SUNYAC in all their sports. And the SUNYAC is only a D3 league.
When SUNY allowed their four university campuses (the other being Stony Brook) to move up to D1, they did migrate from D3 to D2 and then to D1. However, by that time, Buffalo was not going to bring their hockey program up to D1, so they dumped it, leaving just a club team.
(P.S., Joe, did you really think I could be wrong about something concerning a SUNY school? )
But i was right as there wasn't a D-III back in the days of blue line icing.