I would side with buyer if original manuals would have been printed material. I tend to pay more for used gear if original manuals are included because I assume ower(s) took better care of the equipment; original manuals for vintage gear can fetch relatively high prices on eBay - I paid $50 plus shipping for an original manual for a vintage high end tube unit.
This is even more important for original boxes and packing for the same reason, AND also because many manufacturers require gear to be shipped in original packaging for when shipping for warranty and other repairs. I paid over $60 for Audio Research box and packing when I had to send in a used unit for repairs. The toy analogy does NOT hold.
The seller should have CHECKED what was in the envelopes when listing - seller was hasty constructing the listing. None of us would accept high quality copies of missing manuals when we purchase new gear, therefore copies are not the same.
Of course the seller invested time to correct his MISTAKE and lucked out that original paperwork was not "printed" material. Of course the copies would have the same information but is that the only purpose? If buyer decides to sell the gear to me in the future, he will get more for it.
In summary, to a buyer/collector, original manuals can be important. Copies are not really valuable these days given the internet; anyone can have a high quality copy made for $10 to $20.
I DO NOT THINK IT IS FAIR FOR THE SELLER TO DETERMINE WHAT IS UNIMPORTANT TO THE BUYER.
I was not the buyer in this case, the two Audiogon purchases I made were great! If Audiogon FIXES there site I may make further purchases (got that in!).
