He probably doesn't know. It is a 273 if correct in a 67 a body in 68&69 it could be either 273 or 318 LA
check out the vin for correct engine then numbers on the engine
But really if a nice car and just a 2 barrel doesn't change the value any in my book if it is numbers matching or not. Condition is what brings the value up some unless really rare muscle car. Even a small block Formula S doesn't bring that much more money over a standard Barracuda.