Well the seller is IMO ignorant of the fact that the earlier S&Ws always bring a premium. Nothing against a 14-2, but its a 3 screw design, at least the one pictured appears to be.
These K-38s / model 14s arrived in 1946/47 as the K-38 target masterpiece. 6 in heavy barrel, 38 special, with any combo of target grip, target hammer, target trigger as options. In 1956 or so, the 5th screw was dropped (upper side plate) and then in 1957 they were renamed the model 14. In around 1964 or so, the trigger guard screw, aka 4th, was removed. While these changes didn't necessarily lower the quality, the popular opinion is that the 5 and 4 screw guns were overall better than the 3 screw ones. Bangor Punta acquired S&W from the family around 1965 and guns made after the acqusition are said to be a lower quality overall by many people. Although that era of course produced some damn good guns as well.
K38 / model 14s have an excellent reputation as shooters and are getting to be collectible in the early forms. If the gun he calls a "K-38" is an actual K38, it should have a screw in front of the trigger guard (4 screw) status and possibly a screw in the frame directly in front of the hammer (5 screw) status. It also will not be marked "MOD 14" or any of the like inside the crane (the part of the frame revealed when the cylinder is opened).
So both are $549 - what do you do? You gotta buy the K-38 because its either a 4 or 5 screw gun which is more valuable. They are connected with the pre Bangor Punta era of S&W where they were still making guns that were damn near pre WWII quality. The bangor punta guns, such as the 14-2, (an early 14-2 could possibly be pre banor punta) did not have the same consistant quality as earlier guns. They also came up with the 3 screw guns in that era. Of course, you could have a bangor punta gun that is just as good, but its not just as valuable regardless.
The added bonus I see here is that the gun he calls a K-38 has unrelieved diamond target grips. Those grips are worth $100 or so alone. They were only on K frame guns as an option prior to the mid 50s when the relieved version came out. Pretty neat that the gun still has em on.
The same gun also appears to have the target hammer with a standard trigger which is a little better for shooting than a standard hammer. Now believe it or not, the other gun has relieved diamond targets, which are nearly as valuable, well over $50 on ebay. It also has the target hammer / std trigger combo.
Both are fairly priced, but the K-38 (if it is) is the better deal from the pics and info you gave.