Quite a few artifacts have been recovered from the Monitor. This is the Dahlgren gun they brought up a number of years ago (conserved in a water bath).
Attachment 93492
It, and other items, are at the Mariners Museum and Park in Newport News Virgina, near Hampton Roads. https://www.marinersmuseum.org/
There have been countless films and documentaries that cover the Battle of Gettysburg; some pretty good, some -- not so much. If you haven't already seen it, I think you might enjoy the 1993 production 'Gettysburg'.