Greetings and apologies in advance, but I can’t figure out which vintage SOG Tigershark that I have. I’m trying to narrow the date down that I bought it new, but the best that I can say right now is sometime before 2005. The knife in question has the Square SOG Logo, it is (was) gray, serrated, kraton handle and came with a kydex sheath. Any thoughts as to what steel this one may have been made out of? Thanks.