... sell them all on private sales.

By you publicizing that you have "a lot of them" and then putting them on the open market, you would have destroyed their market value and hurt a lot of collectors unintentionally.
The price could have dropped below $100, not because they weren't "rare" any more, but because the market would've been temporarily oversaturated; then, the price would stay low because of the new perception.
I believe by you now saying you now just "have more than one", probably means a certain someone has already contacted you

That's what happened to the $7 McCarran when XXXX bought about 15 of them "under the table". Before, the price was a stable $150+, now it is $50-70. He dumped them for a quick profit and destroyed the market for them. It's pretty hard for the market to recuperate from those kinds of actions.

But, this is just an opinion, so come what may.