Kaye, that's why I suggested a professional auction company that has expertise with firearms specifically or other collectibles. They have the staffing that can research and ascertain what is original, what is a good reproductions, etc. They also will be able to take and post many dozens of high resolution photos documenting the stuff that serious collectors are going to want to see before bidding. Then a few months down the road they'll offer all of that in a competitive bid auction that clearly spells out to the bidders the terms of the sale, acceptable forms of payment, what can be transferred or shipped directly to a purchaser, and what would by law need to be transferred to the buyer/bidder via a FFL in their area. It will all be marketed in various formats and publications both printed and online that will attract the broadest number of interested buyers/bidders.
^^ But all of that comes at a price too, and a reputable company will explain those costs as well as buyer premiums so that it should be pretty clear to you. Any other type transaction that you enter into with a local firearms dealer even is going to have costs associated with it also, since the way they make a living and stay in business is "buying at wholesale and selling above that price". In a one on one face to face transaction if you knew the value of a piece, a buyer is still likely to try to weedle the price down since they know you don't have a brick and mortar store, or that you aren't incurring auction fees, appraisals, or commissions.
But none of that can be accomplished by a few pictures on a forum, especially out of focus pictures, or low resolution screen shots. Also it would be extremely unlikely that you could safely offer them on places such as gunbroker.com since you don't know the history or value of this stuff yourself. If you did sell on a site such as gunbroker, then you are tasked with properly packaging and shipping them yourself. You would also be tasked with trying to ascertain what can legally be shipped to people and what would by law need to be shipped to a licensed FFL holder in the buyers area. And then you would also be the one who had to deal with freight claims if they arrived damaged, or you might be dealing with a buyer who refused it and wanted a refund by claiming that it wasn't as advertised.
So if you have numerous pieces of your late husband's collection that you are going to be offering I would suggest reaching out to a source such as this: (there might be a similar entity in your neighborhood)
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https://www.rockislandauction.com/