The easiest and least costly option for you is to get small chrome hole covers. They are little chrome plated buttons that basically fit inside various sized holes. Getting a new set of reproduction bumpers is many hundreds of dollars, getting your original bumpers repaired by welding, and then re-plated is thousands.
Sometimes they are called tubing covers, and you may have to search a bit to find ones in the right size. Here’s what they look like.
Personally, I’ve never minded my bumper over riders, and thank goodness I had them on the trip to Chicago for Pagodafest. I was able to loop a fan belt over them and hang my exhaust system from one!