Okay, then, there shouldn't be any issues with maintenance. For some reason, I was under impression that you are in a different situation, like many other folks
The 51 looks very promising. Appears to be an older repaint. Likely, just needs the standard maintenance (mostly everything 😁) and a couple of gauges repaired. For $6500 I would take it right away, unless you have cars in better condition available. I assume that the little is in hand, and the engine number matches the frame and the body? 😀
Also, if you have not already done so, take a good look underneath the car, to make sure that there are no surprises.