Nothing Major.. Just an over-polished Die issue. Common find on Cents from late 1960's and early 1970's.. No premium
The photo gets blurry when I try to enlarge so I can't tell if the Designers initials are present. I'm not seeing a DD but the roof appears not to be attached so yes to a floating roof variety.
Now when I posted a 1970 floating roof with no initial on another post u gave it praise saying good find now u say there worth a penny which is it
Depends, are you looking to get rich quick off of coins or actually become a collector and keeper of history?