Personally I think that is high for the older production units. The new production from Marklin is MUCH higher. The PRR F7 A's seemed to be going for about $350 a few years ago with the F7 b's going for about $200. IF you shopped carefully you could get a set around $500 NIB. There were folks selling non running or poorly running & Heavily used F7 A's on Ebay well under $100 for a while too. I think that the NYC paint scheme was not as heavily produced though with the B&O being the "rarest" paint job.
My 2 cents and opinion. Bottom line, it is worth what you want to pay for it or sell it for.
Chas