hello , I am not a pro but HVAC is complex stuff and that label sounds clear enough. I would never do it.

Thanks, captree. Yes, the HVAC is complex. The reason I posted was because two different HVAC companies came out and looked at the unit and gave quotes for moving it and said that they could mount it vertically in the new location. I was wondering if this sounds correct.

There are kits to convert some horizontal furnaces to vertical. An HVAC pro can do it.