There is a very small crowd of people like us that are interested in these old smokey,reliable,noisy german things.
Perhaps you could strike a deal whereby you give the guy 500.00 now, to hold the car for you for a month or so, and then give him the balance at that time, if your $$$ position permits it.
I've done it a couple of times before with good results.
My .02 cents
Have a great holiday.