I did some research on both homes of EPG/Prevue/TVGC.
The original home of 3801 S. Sheridan Ave in Tulsa is up for sale. For a little over $4.525 mil, you can own the original headquarters of EPG. Currently, Platt College is leasing the space. The building was built in 1982, which would be just after EPG started its business.
Secondly, I was able to find that UVSG didn't move into the Lewis Ave location until early 1993. If you search for Kensington Galleria, which is the name of the mixed-use mall, search for an article from tulsaworld.com and subject "Dillards Leaving Kensington Galleria." Per this article,
The converted area was renamed the Kensington Office Center. A little more than 30,000 square feet will be retained for retail use. United Video Satellite Group, a locally based satellite communications and marketing company, announced a couple weeks ago it will move into the Kensington Business Center. It will occupy 105,000 square feet.
The article date is Jan. 27, 1993. Interesting enough, this would be the same time that the blue grid came out. So that would mean that all of the development of both the a2-black and a2 grid would have been done prior to the move.
And a last research tidbit, I found a magazine article online where UVSG also housed Zephyr Weather Information Service in this same location back in 1985. This would be the weather data information that would have fed some of the Character Generators available to cable systems. One would wonder if this is also where the weather data information came from to serve Prevue Weather?