Bruce, both things are correct. The MIC Guilds continued to use two truss rods in the neck for quite a long time. Not sure if they still do, but I believe it's been changed.
The transition in Tacoma happened as you said, I believe it was late in 2007 actually, but I'm not sure. It was one of the last big change orders that the Tacoma shop actually acted on. Later, in the New Hartford era, they changed the actual truss rod that they were using in the 12ers to a dual-action rod. I don't know if what preceded it was a standard (single-action) rod or just a different dual-action rod. Neck manufacture in New Hartford was highly influenced by equipment and processes that came from the Ovation processes, by the way. The giant CNC cutter that they used to shape the raw necks was an unbelievably cool machine - that was inherited from Ovation. But, in any case, all NH 12ers used the single rod flanked by fixed carbon rods technique that came from Tacoma-era.