These are heavy wires, not thermostat wires.
On 2020-09-11 by Anonymous Thanks, I read through that but the Orange and Blue Wires were not used and there is no C on the therm wiring lug.
I would suggest going to the furnace and see how they have connected the thermostat wires to the control board.
You would need to see where these three wires terminate to be safe.
Do you have a C-Wire? Any help would be greatly appreciated my old thermostat has 11 terminals with 9 wires connected and my new one has 9 terminals.
Do you have a C-Wire? Try to find out if you have a common wire running up to the thermostat or not by using a volt meter with the power on and testing between any two of the wires.
Description: Here is the link to that page: The tech should have traced the wires for you and I would not think that you would need any changes, but it would not hurt to check the wiring.