This brochure says it has leaf spring suspension - no options mentioned as to air suspension, as you said.
Also, I have read about some concerns with the cable system used on the slides. Check to see if it is one of the 4RR chassis that are on a very expensive recall that would be at your expense, since the Monaco corporation that built it went bankrupt, and the new Monaco corporation apparently will not honor the recall.
Others will no doubt chime in with experience on this model.
Have fun looking!
Joe and Debbie, Emma the Aussie Cattle Dog who adopted us
2012 Discovery 36J, Blue Ox and Air Force One, 2010 GMC Acadia Toad
USAF (Ret) WDØM https://wd0m.com