I'd guess new old stock.
However, with the renewed interest in the 3rd gen autos since they've been discontinued I could see S&W deciding to do a limited (or maybe not so limited) run to capitalize on it. I've recently become more interested in the 3rd gen autos myself and if they would be to do a run of them I'd highly consider several (especially a 4000 or 3900 series compact, a stainless 908 or a 410/411). Though, they recently (i.e. about 2 years ago) completely stopped supporting the older guns, not even regular wear items like springs are being made or carried by S&W anymore. Also, what seems to be a renewed interest on some websites (mostly S&W related), probably isn't so widespread. So, realistically it probably isn't likely they did a run, and it is very likely NOS (if it isn't just a really clean used gun).