The RCA VBT-200 was definitely the first VCR sold with the LP speed, but the first VHS machine was the JVC HR-3300U, in early 1977. If I remember the details right (because I was following all of this stuff constantly as a teenager then, the way a "normal" guy follows sports or girls or whatever), RCA wanted a video recorder that could hold an entire NFL football game on one tape, and JVC would have said "no" but their corporate parent Matsushita said "yes". RCA got their VBT-200 on the market, and Matsushita's Panasonic brand sold it as their PV-1000. I have forgot now if there were other versions/"clones" of that two-speed machine.
Two years after the VBT-200, the Super Long Play/Extended Play "six hour" speed arrived in the Panasonic PV-1200 and RCA's VDT series, and a whole bunch of "clones". I remember these brands for sure: Quasar, GE, Magnavox, Curtis Mathes, Philco, Sylvania, J.C. Penney, and probably Montgomery Wards. (If you know of other brands of that rotary-tuner, angled-front two- or three-speed VHS machine, please let me know.)
Now, almost fifty years later
, the "VCR wars" seem almost comical, with all of the constant leapfrogging and partisanship, but they sure did spur the manufacturers to make lots of impressive improvements in home video recording technology and performance very quickly.
I do not remember hearing of JVC "forbidding anyone" from doing anything, but they definitely never made any VHS machines that could record in the LP speed. JVC was also a/the supplier of VHS machines to Zenith, so I presume that those are SP/EP recording machines only, also. It would surprise me if any Matsushita-built VHS machines after the PV-1200 could -not- record in LP, though, except maybe once Super VHS arrived. (I never had one in those days, myself.)