Gerber also moved away from the Sandvik steel and used the 420HC in the interim. I can't remember the exact dates (I've posted them somewhere else in this forum), but Gerber was having trouble getting the amount of 12C27 steel it needed for production...so they went to a 420HC temporarily. I also can't remember what blade steel they settled on.
bladeforums has the exact information you're looking for. ETA: found it, and listed below.
IMO, the LMFII is still one of the best values out there. Solid construction, good sheath, and paracord/belt cutter all for around $60-70. Tough to beat.
ETA: 12C27 and 420HC are fairly close in cutting/edge holding and you'd be hard=pressed to tell the difference. I might be upset if I ended up with a 440A example, but it seems that was only produced for a short while.
Now
Here's the info:
***NOTE*** January 2006 – December 2007 this steel type was comprised of Sandvik 12C27 SS.
***NOTE*** January 2008 – April 2008 the steel type was temporarily changed from the Sandvik 12C27 SS to 440A U.S. SS.
***NOTE*** May 2008 – current: Production had not resumed with the Sandvik 12C27 SS due to complications with material availability, but switched to a more closely matching steel, the US 420HC. Below is a chart comparison between the Sandvik 12C27 and the U.S. 420HC products: