Apologies in advance if I actually have no idea what I'm talking about. I was going through some Lincoln cents and the mint mark looked off to me on this one. I will post four pictures, two of the coin in question and two of another 1979 D that appears to look more normal to me. I took the pictures with a lens from a broken projector and a cell phone, so they are less than ideal. Hopefully they are good enough.
This one could be RPM-001, but it's hard to tell from your image . So you'll have to check for yourself . http://varietyvista.com/02b LC RPMs Vol 2/1979DRPM001.htm
That's the coin I was referring to, but it seems I am likely mistaken. Oh well, the search continues. Thank you everybody for your answers.
The mintmark position on linked example looks as if it's in a slightly different position. That said, and with the understanding that even if an RPM it would be an exceptionally minor one worthy of no real premium, if you can take/post clearer photos, please do.