Now that the bug has bit, I would like to get the proper top box for the big bottom box I have which is a 1968 KRA-378, I'll attach the catalog page. Would the KRA-57A be the proper top box to go with the bottom box?
Speaking generally, not just for Snap-on, the best source for original badges are original boxes that are beyond preserving or restoring. I have bought several Craftsman boxes and one Snap-on box that were cancerous with rust just to cannibalize and re-sell the badge here or on eBay. I junked the boxes. Those kinds of boxes are not easy to find, but they do show up at flea markets from time to time and are often dirt cheap. Cheaper than buying the badge from someone with the same idea on eBay.