Topic: NES Copyright Differences on Bottom/Back Decal

Hey all,

New to this forum, so if this has been brought up before, I apologize. I was looking at a bunch of games, do the copyright markings on the back or bottom of NES game make a difference in the release date? The Super Mario/Duck Hunts that I own have two different copyright markings. One has like a weird "M" in a circle, and the other has the traditional "C" and "M" plus the year 1985. Still other games have just read "Nintendo" with no date and no copyright. All of the have the registered trademark, but I was just curious it those other differences help find out a loose time frame of when they were made. Thanks for any info,

G