2002 E350 SMB with factory installed air compressor?

[FrontmanAdventures]

Hi all, trying to track down where this fitting goes, and some have said propane (rig does have the tank, but I've never seen a propane fitting like this) and others have said on board air, which this fitting appears to be, but... did SMB ever install factory air on the rigs as an option? TIA

The fitting is located on the passenger side rear, near the leaf/rocker area, and has a little rubber cap. It's definitely an air hose fitting, but it'd be super cool to have propane there for cooking on a tire table, etc. What say you?

[REF]

Photo please……

[arctictraveller]

Can you follow the line and see where it goes?

[FrontmanAdventures]

Well, until I figure out how to post pics again (been years since I posted to a site that didn't host photos) here's my FB page and I just posted up a pic - https://www.facebook.com/frontmanadventures

[FrontmanAdventures]

That's the plan later today. It's in the shop getting new sway bar bushings, should be done around noon