Curious to know how old this box is. I recently bought a really ancient "Canuck" box of 20ga and it looks similar to what OP posted here in terms of the age of box and font.
People have sold the Kleanbore boxes online. It's nice that you have these with shells in it too.
There are some websites that show Remington old packaging but unfortunately they predominantly non shotgun shell rounds. Though based on that as a hint, we may be able to surmise the age of these, give of take 30 years...lol...
Are you selling these?