I believe the "Dallas" Churchills are late guns in the company's history, finished off at a time when company was in trouble -- hence, perhaps, the perjorative aura some associate with them. That said, I've seen some good ones from that period and some OK ones. To be honest, though, you can say that of Churchills for much of their history -- it really depends on who was building the guns. Their trade suppliers varied, even at the same point in time.
The magisterial history of Churchills by the late Don Masters gives a good account of the auction. I don't have it in front of me but I think it even shows the serial numbers.