Well sure, if you want to get downright technical ....... sure, don't ever find anything 50 yrs. old on any speck of federal land. I don't think the issue here is CAN such stuff like ARPA be said to apply , but rather, does anyone really give a hoot ? Example: I can hunt Ft. Ord here (WWII era origins) till I'm blue in the face. And (gasp) find a 1950 wheatie or whatever. And truth-be-told, does anyone care? No, of course not. But did that mean that if I asked enough archies and lawyers in Washington "can I keep this?" that I might not find one to cite ARPA as the reason I can't ? SURE!
No mind you I'm not saying to throw caution to the wind and tromp on obvious historic sacred monuments. I mean, OF COURSE use common sense. But if you want to start getting technical and digging up deep minuita, I gaurantee you that you can find verbage at any level, (city, county, state, or federal) that .... given enough questions of enough people, can preclude you from detecting even a modern city sandbox.
No mind you I'm not saying to throw caution to the wind and tromp on obvious historic sacred monuments. I mean, OF COURSE use common sense. But if you want to start getting technical and digging up deep minuita, I gaurantee you that you can find verbage at any level, (city, county, state, or federal) that .... given enough questions of enough people, can preclude you from detecting even a modern city sandbox.