Others have indicated your TT date and the VIN do NOT match up in time... so if the VIN is the original one (ie. .. matches the hidden VINs), then the TT has been changed, but that TT is basically a 'manufacturer's plate'.. same as that little plate on the back of most refrigerators, computers,e tc.. which identifies the model number, mfg, etc.. your car will run just FINE without a trim plate.. and it has nothing to do with ownership. It's only critical if you are *showing* the car in original classes, or 'playing the matching numbers' game..
Note: If it's true what was posted earlier, that your VIN was for a December built car, and your TT was a September date, then it seems beyond possible that they both were on that car from the factory.
What you should do is this:
1) Check the hidden VINs against the title VIN and the displayed VIN on the car. if these do not match, DO NOT THINK ABOUT purchasing this car. you could pay good money for it, and then have another owner claim the car and you LOSE... everything.. car.. $$$$.. money everything. You should suggest the current owner run the REAL VIN (the hidden VIN) with law enforcement to check if it's stolen (but DO NOT BUY IT)..
2) IF the VIN's all match, assuring you that the title is the correct one for this car, and you are buying it from the titled owner, and if you like everything else about the car, then you might want to buy it... you WILL be the legal owner per the VIN and title.
The TT has NOTHING to do with legal ownership.
PS. Kurt indicated that he thought the VIN was probably changed, but that would indicate a STOLEN car. IMO that's less likely that the TT was changed out. LOTS of people change our the Trim Tag simply to make the car look more desirable (ie. take one from a September car and put it on your Dec car). It's NOT a good thing, but it's not illegal, although it's unethical and immoral... and it's done to *fool* people (namely buyers).