Bicentennial Quarter DDO

[Shleppodella1]

Now this is a Denver obviously and the mintmark is mushy-filled but the date looks to be doubled and not machine and all I'm finding on this is the FS listing which this obviously is not.

[MintErrors]

In my opinion, it looks like machine doubling because the numbers are not any wider than a normal number.
It also is lower and shelf-like.
The D appears to be circulation damage or wear and tear.
The second photo of the date shows some copper above the second 7. Its difficult to see whether this may have affected the area of the mintmark, like a coin rolling machine or a coin counting machine.

[Shleppodella1]

How to tell between this and class 3 then please?

[MintErrors]

Here is a write up by James Wiles on Class 3 doubled dies.

http://varietyvista.com/25%20What%20...bled%20Die.htm