Oh, I suspect that's true..> My hunt areas, though, are modern parks. If I'm finding iron (I used to try to find interesting things), they fell into the category of "bulldozer ends and pieces," "Lawnmower blades," "Soccer goal spikes," and the ever popular "Front quarter panel of a truck" (I'm still not sure how THAT ended up under the sod).
After digging that kind of iron for months, with no actual "relics" coming out of the modern soccer fields, I gave up, and now discriminate.
Wish I was in an area that had a longer history than 70 years. And 30 years ago, when my Dad grew up here... there were less than 5,000 people. Now there are 77,000. with over half that growth in the last 10 years. This of course, explains why all of our parks are "modern" and installed in the last decade.
OH... and one other thing... 20lbs of Iron in my bag makes for a sore hip an hour later. I've done that, too. LOL
Cheers,
Skippy