Lithoform Engine's last ability only copies a permanent
spell. You can not copy a 3/3 Phyrexian Golem Token, or any other permanent on the battlefield for that matter, because none of that is a spell. It has to be on the stack to be a spell.
For example, you cast
Master Splicer. Before it resolves you can pay an additional 4 mana to to get a second
Master Splicer. The copy Splicer will enter, make a golem, then the real splicer will enter and make a golem. After which not a single one of these are viable targets for the Engine's last ability.
For
Mr. House, President and CEO to work with the
Lithoform Engine you need to pay 2 and target his triggered or activated abilities while they are on the stack.
Actually, rereading that, are you talking about the deck builder rather than the actual function of the cards? In that case, yeah it should be making copy tokens. There are just some cards that make copies that slip through the cracks, I know of
Delina, Wild Mage getting overlooked for sure since my deck for her won't put one in for her with the Detect Tokens function.