With Hot Stampers the idea is to get a mix of stampers on an earlier pressing, each of them fresh, to get the best sound. So it would likely be a US pressing very early in the run. But it doesn't have to be a true first - firsts off of worn-out stampers would theoretically sound less good. It's probably 99.9% bullshit but who knows. I just buy stuff that looks and smells clean and try to be happy with that.
Oh, checking the Morgan - it's a rechanneled Liberty stereo from no earlier than 1968.