Hi Gary,
The first thing you have to understand about this forum is that some folks have a way with words at times. Every forum has its pluses and minuses. Takes time to know people I reckon; some you never do.
You are most fortunate to own two Navy like; or originals. I have no idea which, but both are certainly more valuable than the run of the mill, run over by a tank four times, Luger. How much, I do not know or really care just talking plain. Navy pistols are faked everyday, originals; if they can be truly evaluated; are getting more rare. Provance is from historical paperwork, not from I saw three of these here in the states, and they are all the same.
If I was really thinking of selling said pieces, Simpson does offer a service for evaluation. Costs money of course, they do not run a museum. By now I am sure you have a lot of private emails inquiring on said pieces. You sound a bit more knowledgeable than the postings let on. I would counsel to sell only when you are comfortable and can live with the number. Once sold, you kinda have to move on sorta speak, because like the stock market things can change in the environment; once you have played, you have played.
I share the thoughts on security on forums/internet services; we do all we can, but it is a battle. No use in making it easier though either. You have to live with those types of decisions.
Gunshow folks are resellers, just like many collectors here and on other forums. They buy as low as they can, and sell high as they can.........tis called capitalism I reckon. There are a few that are in the collection way, because of the history/gleam of the pistols, but those folks are getting older, sorta the great generation we hear about in other venues. Knowledge is a key as you well know, either your own schooling/experiences or from a trusted knowledgeable source. The environment can kinda be like the 22lr guys that buy from the big box outfits, and then go to the gunshows to resell.
I got out of the collection type arena years ago, but still have an interest in the Luger pistol. Rare pistols like yours (maybe, if original) have some value that sometimes is hard to place, remembering the times that we are in now.
If you want just a general idea of current values, and I use that term fairly loosely, I would just hit the various large storefront Luger sites, and compare to the pistols in hand. If you are looking for a relative, today's type value; it will take some footwork and usually a fee. We all enjoy keeping our shirts you know........
I for one enjoyed the pictures of said pieces, not every day we see the two position rear sight anymore.