I agree with much of your thread. I too agree there is more value in that example as a collectable than one might assume at first glance. And of course you hit the nail on the head, that the restorer would need to be honest about the restoration process.
Unfortunately, I have become somewhat cynical of the high volume sellers. An easy way to increase profit in re-sale would be to simply swap the back of an existing 128K with a later manufacture date. In my experience, the 128K with the earliest serial numbers tend to fetch the higher prices. An easy increase in the profit one might have reaped from the same sale. Also, some of these sellers have a big problem with UPS damaging an awful lot of these 128Ks. Most of the damage tends to be around the bezels I've seen. A quick switch and the 128K is back in the black. Of course the problem with that is as Eric points out, the history of this Mac is well known, yet likely not imparted by the re-seller, not to mention the original 128K analogue board which has been overtaxed and heavily used as a 512K, also undisclosed to the buyer, who may well end up with a Mac he paid high dollar for, that dies shortly after acquiring it. Another likely scenario is that a seller has acquired a number of spare parts for the 128K, either individually or from a so-called "non-working" system. They turn up on eBay all the time, often for very little money, including the logicboards. Only the complete working systems tend to command top dollar. So constructing a 128K from scratch might not be as difficult a proposition as supposed. This is most easily illustrated by the bits and pieces of the original packaging from the disks to the box, sold routinely on eBay and eventually put together to form a complete boxed system that fetches far more than the individual parts.
Not to belabor the point, but one incident in particular left me cold. A "reputable" high-volume seller posted detailed pictures of an early Mac 128K, with a picture of the logicboard from a late run model, selling it as a stock original. A few well placed questions later I discovered the seller backpeddled from several positions he took to explain the discrepancy and ultimately said it was the wrong picture. None of the conversation was included on the auction and the photographs were not changed, though the auction specifically stated the buyer would receive exactly what was pictured.