Whether or not heat pump shows up on the thermostat is, I think, controlled by dip switches in the control board in the inside unit. If that was set wrong, or if the overhead unit was changed and controller not reconfigured, it may be showing Heat Pump even if your unit doesn't support that feature.
I suspect the only way you can find out for sure is to remove the cover from the rooftop unit and read the label to get the model number. An AC tech could probably look at it and spot the reversing valve, and maybe you can. I wanted to find out what size unit was in my trailer but there was no label for the roof-mounted part visible even after removing the shroud from the inside.
“You cannot reason someone out of a position they have not been reasoned into"
Al, K5TAN and Missy, N4RGO WBCCI 1322
2002 Classic 30 Slideout -S/OS #004
2013 Dodge 2500 Laramie 4x4 Megacab Cummins