Also from 1965-1967 there were
no mint marks on the coins those years. Even though they were struck in 4 locations, none had mint marks. In 1968 the letters were touching the rims on all coins, but this actually started developing earlier, it just was a widening of the master hub over use for several master dies created each year. (up to this point, two were made from the master hub and the Working hub and dies were made on down the line)

Then in 1969 they made a new master hub. Thus the devices were in the right spot again:

Then about 1982 they need a new die for the small date cents and thus you had a Large and small date that year.

So these look about the same from these two images, so what is different? Lets look closer:


But everything on the 1967 is normal for that time. the coin does look a bit weak, but it may have had a small acid bath. Hope this helps. It doesn't all come to you over night.