He doesnt need to, but I think he would have done this. Oda simply could have drawn him holding the copies in his hands or something, but we didn't see them at all
Both crews will return. Law is a D after all, and I also don't think that Oda wrote Kid out of the story like this. They both still have goals to complete. I mean, Oda couldnt even kill Kinemon.
Which is bad writing for me, but thats another topic. They did not earn them by themselves, they waited for weaker crews to collect the porneglyphs and cross their paths. Doesn't make them look good as yonkos at all, especially Shanks.