Questions About My First Coin Roll Hunt (Pics Inside)

So I decided to pick up a 25$ box of pennies to see if I could find any of the key 1920s dates I'm looking for. I was expecting to find mostly pennies from the 70s, 80s, 90s, 2000s but instead everything in my box was 30s,40s,50s,60s and only a very small amount of 1970, few 1980s and only 10 coins out of 2500 from the 2000s...I found it very strange. Why is this?

Here is a picture of what I mean:


From left to right those piles are 30s, 40s, 50s, 60s, 70s...

All of the 30s pile is 1937, 1938, 1939, almost like the George V pennies had been removed?



I did find 2 rolls worth of 1967 pennies and these ones that were in good shape:



A lot of nice uncirculated even maybe some MS 1960s and 70s coins:



And lastly I did find 1 George V penny, its a 1929 but it has some damage.


The other 3 pennies in this picture seem to be very deep, the edges of the coin are much higher than they should be, what is this?

Any thoughts about this box? Why so many 30s,40s,50s,60s but no George V and nothing recent?

Thanks!