Have i bought a lemon?

No offense but not noticing lights during a vehicle pre sale inspection is letting excitement override logic. I went over my Boxster with special lights to look for filler lines in the finish, checked the vehicle mechanically. It's true what others said about buying cheap and paying if the PO was a poor steward of the vehicle. If the head gasket is solid then maybe you'll get off light, I suspect with that mileage you have deeper concerns, a raby upgrade and a clutch kit would be a sweet option if the engine is coming out..good luck

My fellow captains once noted that BOAT meant " bring over another thousand", welcome to land boating my friend...