Sorry about late posting, just been busy.
Official answer from Spektrum was that it will work. I suspected this because both receivers bind and controls operate as programed.
The bigger question was what happens with telemetry, which I have no desire to monitor, at least at this point.
The AR620 receiver reports telemetry when within 450' of the transmitter, while the AR8010T reports within this range and further. So, when the plane is within 450' the telemetry reporting will conflict with one another and basically cancel out, i.e. no telemetry messages. was out of this range, the AR8010T will continue reporting.
As far as the binding procedure, you have to bind each receiver independently, not both at the same time.
So, I bind the AR8010T and once bound I turn off that receiver and the transmitter. Then I bind the AR620 and once bound I shut that and the transmitter down. Now when I power up both receivers are working.
Also, both receivers must operate at the same RF speed. Basically if you use multiple receivers of the same manufacturer and same protocol, you are good to go. no DSM2 with DSMX, no 2048 steps with 1024.
Happy experimenting!