1994 GMC Van heater cold

Does the engine reach normal operating temp, according to the temp gage on the dash?

With a warmed up engine idling and the heater turned on, can you feel of the heater hoses under the hood, are they both hot?

Sometimes I check for coolant flow through the radiator, by removing the cap on a cold engine. I have drained the coolant down so I could see the top two or three coolant passages in a cross-flow radiator. Start the vehicle, if I see coolant flow instantly through the passages, something is wrong, I check the thermostat. If your radiator has a tall neck where the cap goes, you may not be able to see those passages. It was just a thought.