There's a slot in the tang alright; when exactly did Flues SBTs have safeties? Considering you're getting about half a gun and probably a bad barrel, price should be--probably nothing. You can find a nice tight one with some color on the sides for about 1200$ least I did and no razeed stocks or other "generational" stock mods. Buy like I did from a rifle/pistol dealer; they don't appreciate them and sometimes don't over-appraise.

jack