Sig M400 Tread Pistol

I came across one of these for super cheap. Are these any good for a beater truck gun? There's not much info about them that I can find. Seems pretty run of the mill, 11.5" barrel, A2 FH, etc.

Anybody here own one or know much about them? I've had good luck with Sig pistols but have never laid eyes on a Sig rifle of any sort.

Thanks