The GPS that originally came in that unit was a standard low end Garmin Nuvi 1450 unit, nothing special. They have been discontinued so it's doubtful you could find one. I changed mine out for a larger Garmin RV760 and used the original dashboard mount so it looks like it belongs there. The RV760 is also discontinued but some are still available. Garmin has two new RV units now which I would recommend you look into.
2012 Monaco Knight 36 PFT
2019 Jeep Grand Cherokee Overland
2005 Jeep Rubicon Unlimited on 2007 16' Car Hauler trailer.