thermostat cause seizure??

hi guys, well motor is toast, done main bearings, it had started losing coolant, then the next day started rattling and then nothing, seized!
so tore her apart trying to find the cause, popped the stat in a glass of boiling water and no movement, but could this have caused it to overheat and seize, only reason i am curious is im putting a new motor in and want to make sure i dont miss anything ,
water pump looks like new, could it be the radiator?

I would replace both

yes, it could case the truck to overheat, which then kills the engine. for the cost of a tstat I would replace it.

yeah T-Stat is toast as well and for the cost of a T-Sat and for just the piece of mind....i'd replace it fo sho!