I'd also bet on 440A. That had been their standard stainless for a long time. I have one of their stainless TL-29s and a Camillus-made Buck 307, and I don't have any complaints about the steel itself in either of them. The TL-29's blade is a bit thicker behind the edge than I'd ideally prefer. But the steel still sharpens up pretty nicely, nevertheless.