If the Mac was released with Mountain Lion on it, then Lion is not going to have the necessary drivers to drive that hardware. So: No.
Can I ask what it is that you find "iOS-y" about Mountain Lion that isn't like that in Lion....? I know these things are subjective, but the general consensus (of those that complain about the latest releases) is that all the iOS stuff was introduced in Lion.
There is a lot that is "unfinished" and buggy in Lion which has been fixed in ML.
You don't have to use LaunchPad or any of the iCloud syncing. Other than that, the experience is pretty much the same.