You are most likely going to get a more informative answer at
www.waltherforums.com.
The Transitional / AAA / Walther USA LLC / "Gadsden S&W" Walthers are a tiny subset within the wide spectrum of collectible Walther pistols, and they're relatively recent. It's hard to say if a definitive value trend has emerged, and if it has, it's likely that only a few people can discuss it with authority. I'm not one of those people.
Independent George said:
As far as I know, it's worth exactly the same as any other used PPK/S...
hilfigjp said:
I find that hard to believe. For a quality, sought-after gun, rarity will always increase the value. If there are 100k stamped interarms, and only 10k stamped with Walther USA LLC, its only common sense that something harder to find will be at a higher value.
One potential issue is that many diehard Walther fans regard German or transitional postwar German/French PP-series pistols as prized collectibles, while American-produced versions are seen as utilitarian "shooters" that may be useful for SD (i.e. to supplant a German gun that has become too valuable to haul around in a holster), but have little or no collector value on their own merits.
The collector community is beginning to warm up to the idea that the Gadsden, AL guns are becoming collectible, but this trend hasn't necessarily gelled to the point that the general gun-trading community recognizes it.
Also, as with many newer (i.e. less than 30-year-old) guns that are becoming potential collectibles, you're likely going to see a steep value drop between a legit LNIB or 98%+ Excellent condition gun, and anything that shows significant wear. To cite an example that I'm more familiar with, I've seen LNIB S&W Model 439s sell for $700+, but an 85-90% M439 with no box is generally a $350 gun.