Yes they can be good, IF they had appreciable use, and IF no one else has beat you to it, and IF there is no other developmental reasons why it's messed up somehow (ie.: fill dirt added, or flood silts covering it, or it's under a shopping mall now, or the top 2 ft. were scraped away, etc.. blah blah).
The military guys often had canteen money (change) and the BTUs they wore had those silly sideways pockets, which ...... when sitting wrong, coins fell out easily.
However, bear in mind that some of these temporary bases were shortlived (even if multiple buildings sprung up). There was a building boom of many such bases, and little anciliary locations, facilities, etc... during the war. Many conceivably didn't get built and moved into, until the very end of the war (because .... go figure ..... at the time, no one knew how much longer it was going to go on for). For example, an army air base in my city, was completed at the end of 1944, so saw only 8 months or so of usage. I don't think it even lasted till the Korean war era, as they just disasembled the bungalos and such. It became a city airport thereafter, but the portions that had been military barracks, offices, and such, were very shortlived. So...... if you went and looked at it today, you might be fooled into thinking it was some big affair, because you'd see old concrete foundations, sidewalks, etc.... But all we managed was just a few wheaties, coin-wise, because it was so short-lived.
However, other bases, that had big tent cities, induction centers, and served for a longer terms, especially into the Korean and cold war era, are good for silver. It all just depends.
