My Parents owned Pool Hall and Snack bar when I was a kid in the early 60s. I got to sort through the change every day for the "family collection". I still have that collection and one day I may post pics of the what the average coin from any given year looked like back then.
As most have said you can expect a lot of Wheats. Could be anything. I know I have a half dozen 1909 P's in AG/G.
Indian heads, don't hold your breath. They were still around, but my collection had maybe a half dozen, and that is from a business.
Nickels,
War Nickels without doubt, they were common as dirt. Buffalo's were also very common.
Liberty nickels were very rare but still encountered.
Barber dimes were still around but just barely. Mercs were still fairly common, we had rolls of them.
Quarters are probably all going to be Washingtons. My collection has ONE SLQ. And no Barbers at all.
Halves would be a good mix of Franklins and Walkers, with maybe a stray Barber.
But think about this for a moment. I was a pretty typical kid back then with a pretty typical allowance. I got a buck a week. With that dollar I could buy 8 comic books; or 2 cheap models; or maybe a cheap toy. A kid back then might, might have thrown pennies away (but I wouldn't have!), but I am pretty confident that anything larger would not have been something wasted in a game.
From your description it sounds as though your Uncle threw them into a hole that he could not retrieve them from. Otherwise he would have just picked them up after he was done; if for no other reason than to "pitch" them again. If this is the case then they should be in good condition considering that they were protected from air.
I recently had a similar project where they dug up the sidewalk in front of the local school and I took my metal detector out there and found tons of dimes under the walk. And almost none in the concrete itself. Those few in the concrete were removed with some gentle tapping around them and they generally just popped loose with very little damage.