Do you know what mods came on the car? If you don't I'd post some photos of the underside and engine bay and see if people can help you identify anything.
And I may be wrong, as I've never researched it, but I was under the impression that the ghost cam tune was a 2011 and newer thing.
Purchasing a tuner would allow you to data log, which would let tuners see what's wrong with your tune/car.
Someone else may know what all you can see and what would hint at a tune. I've never messed with mine so I'm no help there.
I'd say it's also very possible that the previous owner had it tuned then returned it to stock before selling it so that they could re-use their tuner.
There's one for sale on here now for a good price.
Now then you'd need to buy tunes (and know what mods you have to order the tune) but you can get a single tune from LMR for $75. Or do tunes for life with various companies that usually charge around $150.