Welcome to the forum, Chris. I think this is the correct owner's manual:
On p. 5-7 [PDF 35/99] there is a section on the inverter, but the floor plans on p. 4-2 [PDF 26/99] do not show its location in the various models. The electrical diagrams on p. 8-15 [PDF 79/99] are basic schematics, and don't show actual inverter locations for the various GT lengths.
Suggest contacting your salesperson for more detail for your specific length GT.
You might also want to check out the Batteries etc. sub-forum, as there are tons of lithium battery threads:
Good luck, and Happy Trails.