I think I got a penny error what do you think?

[Goes4ever]

at first I noticed the D mintmark was all filled in, not sure if that is common or not, so I took a picture and blew it up and when I did I noticed doubling on the date you can see a definite doubling on the 9 and the 6 in 1968, can you see it? Is this a legit error coin?

 

[FingerGrime]

I have found several with filled in mintmarks. I'm pretty sure that their die chips.
As for the doubling, I can't really tell much about it...but its probably machine doubling.

 

[XX]

While it looks like strike doubling to me, it's hard to tell from scans.

Please post your pic in the error forums over at cointalk.org,
you will get a much better response.