Yup, the NEP610 is three feet high.
The blackface '64 would have been a small cab Bassman, the cabs were too small for bass.
Paul had the big cab Bassman in later years, probably the 215 unless he had a 1967 like I do, that was the last year they used 12's in those I believe and I think they only used 12's in the big cab for that year. I got a mid '67 drip edge silverface Bassman with 2 12's with the blackface circuit in it, it has the big cab, it sounds really good. Those cabs were sealed though so no tuning involved except their size and whatever they stuffed them with which was not much, the big 212 cab sounded a lot better than the small earlier 212 cab, lot more bottom. Mine has Eminence speakers in it though, don't know what model but they sound really good.