nah it's a racing/parts shop out by the 696/i-96 intersection called monkey wrench racing. they specialize in celica and the 2zz engine and they sell used engines
AFAIK blown head gaskets are caused by overheating, they don't cause it. Either way it wasn't overheating, that's absolutely for sure. The temp gauge was functioning properly, plus I know the shop owner extremely well and I know it was done correctly and it was even checked by another shop with very competent mechanics.
The engine is completely blown at this point I believe,. Probably due to the fact that coolant doesn't lubricate very well (ie it's not the blown head gasket that caused it to blow directly, it was the coolant in the oil)