Proof set coin collectors may fall into a possible trap to spend more on a proof set than it's worth, with the notation that the set hasn't been opened.

Just some points to ponder, paper ages and discolors, 40 plus year old sets, might be uncommon, especially in a perfectly new looking envelope.

What's to prevent someone going to the local office supply store and buying an envelope close to color of the proof sets packaged? Then printing the same Mint information on the new envelope and packing the old set into a new "sealed" envelope, then selling it here at surplus it's value, because we think there might be a special coin worth hundreds or thousands?

Just remember it's possible, look closely at the picture and if the envelope looks to good to be true, maybe it is.

Even the seller may be lured into thinking it is unopened, therefore, unknowingly selling it as unopen when indeed someone down the line repackaged it.

Some of my recent Proof purchases, where very nice, however, unopen sets, that I couldn't resist to open, I found that sets where missing Certificates from the Mint, the card board papers looked like construction paper cut to size, and the paper inside aged where as the envelope had not.

Unopen is something that you can't necessary blame the seller for, as he may only be passing sets that he previously bought unopen as unopen.

So look closely, think carefully, bid with knowledge, and ask the seller about the origins of the "unopen" proof set.

Happy Collecting