Does anybody have one or know if they were built by Panasonic or General Electric?

I once had one, mine was a thinly disguised GE. I think it was the same as their last hybrid chassis.

Wasn't Grants gone by then?

There were at least 2 Grants, likely others, in Florida, in Saint Petersburg and Port Charlotte until '76 or '77, maybe later.
My father had purchased the set I was wondering about and I am pretty sure the salesman told him it was made by Panasonic but the photo of CaptainMoody's cool looking GE 19" (with doors) reminded me of my Dad's set but his was wraped in a lovely plastic wood standard cabinet. I think the tuner knobs may have been side by side but I was a kid and saw it very briefly, so, it could have been either way. Someday, I would like to get one.

W. T. Grant company died here in western NC in 1973.

I found a Bradford b/w tube type set in the trash one time which was made by G.E., crt was broken unfortunately.

Grant's survived until the late 70s, I think '79? I don't remember them, though I know that Mom had portraits of me taken there several times in the early-mid 70s. My Dad still has a Bradford chest freezer humming away out in the garage. Anyway, I can't think of seeing any re-branded Panasonics.