Thanks again for your question and for your patience JT.
The manufacturer was able to send over a parts breakdown for your APW Wyott GGM-36 griddle. In converting from natural gas to LP you'll want APW Wyott parts 2066850 (LP burner orifice) and 2092904 (LP pilot orifice). If you've already got these, the #55 LP orifice hood you'll need is 20668-48. We can order all these parts for you if you need.
Please give a member of our Tundra Restaurant Supply team a call at 1-888-388-6372, and we'll be happy to get you the parts needed for your conversion.