We have a 2007 FF (x210) that’s likely to have the same brand and perhaps even same model A/C unit as your 189. I just checked and found that the info you are seeking can be found by removing the intake vent/filter cover just in front of the control panel on the ceiling inside the camper. The specification, model number & serial number stickers are easily visible. Be cautious with release tabs when pulling the vent panel down. Like your aged rooftop cowl, the plastic on the inside components may also be quite brittle. In the words of Profdant139, “don’t ask me how I know this”
If you're not livin' on the edge, you're takin' up too much space!
2007 Shadow Cruiser x210, 2004 RAM 2500 4x4 QuadCab SLT 5.9L CTD, Factory Tow Pkg (3.73 axle), HaulMaster WDH