They are both not factory assembled rifles. Doesn't mean a whole lot but certainly brings the price down. They are both A2 style uppers meaning the carry handle is permanently attached. Which is the least desirable version. They are also both 20" barrels. So essentially it would be difficult to get 700-750 for them resale. They do have the quad rails which can run between 50 and 200 so that does increase the value. The DPMS vs Stag lower doesn't mean much since you really don't know what model upper they are. You also don't know much about the lower parts kit. They have the 4 position Model 1 stock so that could mean they are Model 1 uppers. They are plenty quality but if you pay much more than 700 for them your probably not getting a good deal. The AR market is now terrible and you can once again get new AR's for under 700 in a much more desirable setup.
Good luck with the auction