Looking to hook up a 2 wire heat only thermostat as the door with the weiring diagram is missing it's a goodman guso50-2?

The thermostat will use the R or RH=RED wire and terminal along with the W=white wire and terminal.

Well in two wire system polarity doesn't matter.

You can put any wire in the power terminals which will be R or RH

And other in W

Make sure if it's low voltage the volatge should be min 20VAC - 30 VAC