Whistler bought the intellectual property rights to the scanner line from GRE before they went completely under. Whistler is bringing out a similar line to the PSR-100/200, PSR-500/600 and PSR-800, which will give them some time to develop their own line of scanners and bring in some money to pay for it.
Whistler will also be bringing out the WS1095, which will be similar to the PSR-900 that GRE was working on but never released.
So, to answer your question, yes they are rebranded GRE models.
Mike