As Tommy says, Bodie is off-limits to md'rs (and bottle diggers, and so forth). It's preserved in an "arrested state of decay". So .... go figure .... if everyone who visited there "took on little souvineer" with them, then ..... doh ... pretty soon the whole town would be gone. haha. You can pretty much figure that anything of that calibur (standing ruins like straight out of a spaghetti western movie) are going to be off-limits. No matter fed, state, city, or county .... you can just pretty much bank on it.
Maybe if you found a site like that on private land would be different, eh?
But there are sites that might have once looked like that, yet nothing more remains of them. I mean, there are places where old stage stops, saloons, hotels, miner's tent-cities, etc... once were, yet nothing remains there now to be seen. Like if they burned down 100 yrs. ago, and are now a "forgotten memory" and nothing but a lonely country-cross-roads, then THOSE would be the type places you could hunt. But in Bodie's case, it was in a respectable state of preservation in the early 1960s, hence the decision to make this into a landmark.