John's link is the type of grill, any grill that use a rail mount. Trust me the previous owner probably did you a favor and stored it in a dumpster somewhere.
The OEM grills are typically of the same high quality as the air mattress, speakers, and water hose and stinky slinky supplied by the manufacturer or dealer.
Couple of suggestions when looking for a replacement, look for BTU rating, material a d gauge of metals. Search the forum and you will find several posts on grills. Enjoy your new to you camper!
Edit.. Forgot to extend a welcome to the forum!