As jw2n pointed out, it is an O-1 carbon steel blade. I have owned both carbon steel and stainless steel Randalls in the past, and have decided I like the carbon steel blades the best. and before we get into the "carbon vs. stainless steel" argument, I carried a carbon steel 6" Randall Model 1 in the jungles of Central America back in the '80's with no problems at all.
And thanks, ROCK! I'll be home from this rotation the middle of September.
Regards,
Ron