That's how it seems to me from what I have seen myself and heard from several others. I got mine brand new last May, a January 05 model that had all kinds of problems out of the box, got two replacements (both January 05) that both also sucked in different ways and then a third replacement (June 04) that has been absolutely perfect. The first three all had very poor focus along the left and right edges and equally bad convergence, the first and second ones had these vertical lines going through the middle of the screen, the second and third ones had bad color uniformity along the edges and a weird intermittent problem where things would totally go out of focus a few times a day and require restarting the monitor, the second one had a major vertical linearity stretching issue at the top of the screen and the third one even had what appeared to be several dead pixels (yes, on a CRT

). I've heard similar stories from some other people with November and December '04 units.
That was a hell of an RMA experience and I only had so much patience with this since it was around the time of my final exams that semester and I didn't have much time for gaming anyway. At least NEC ate the shipping costs and the replacements were all brand new. Although now that I have used the fourth, good 2070 for four months, I think all that earlier hassle was almost worth it.
From what I can tell the quality control on the great Sony and Mitsubishi tubes completely went through the floor in their last two or three months of production and both manufacturers flooded the market with duds before shutting down their factories. So these days if you get a used or refurbed one, it's most likely one that was made before this period and is probably still in great shape as opposed to the POS ones made near the end.