1953 D Doubled MM ?

I know little to nothing about these coins, but I just discovered a small jar of wheaties I had sealed back in 1976. Upon first inspection, I found a doubled 1955.



In a search, fenton cited Lincoln Cent Resource.
http://www.lincolncentresource.com/..955ddo2.html
And sure enough, my coin is featured as a "Poor Man's" DDO in the section FAQ.
Then I looked at the picture for the sales section and saw a 1953 D, with doubling on the left side of the MM. But no explanation. As I think I found one of those as well, what can someone tell me about this coin?


Thanks