What are these copper pipes and do I need to do anything to them before covering them with a wall?
What are these copper pipes and do I need to do anything to them
before covering them with a wall?

Since they have been open behind a wall for nearly 40 years without an issue i think is is safe to assume there is no problem.
If you do not want to try and figure out where they come from and re-purpose them then just  solder caps on them and build your wall.