No, you can't import it to Message on the Mac. You would have to have been using it since the conversation started. I've used this method when I've accidentally deleted a conversation from the phone and wanted a copy of it.
Honestly, the $30 I spent on PhoneView five or six years ago was money well spent. I made a mistake (yes, it was mine, not a bug) when switching to a new phone a couple of months ago and didn't have any of the ringtones I'd created myself. I was able to easily copy them from my old phone to my new computer using PhoneView. From there, it was a simple matter to sync them to the new phone using iTunes.