It's almost a certainty they are Boeing Surplus. They use those quick release bits almost exclusively. And those particular ones have built-in pilot bits, hence the step. I bought many of those directly from the Boeing Surplus Store down in Kent, WA in the 90's. One thing to keep in mind is that if Boeing throws out an air tool or cutting tool, including drill bits, it must be practically used up. Aside from building aircraft, Boeing is the largest cutting tool user, and largest cutting tool refurbisher in the world. When bits and cutters get dull they are thrown into a bin and taken down to the Boeing cutting tool division in Auburn who runs them through the re-sharpening or remanufacturing lines. It's quite an impressive facility. Many times what you find at Boeing Surplus are those items that have been deemed to be beyond usably re-sharpened and so were shipped up to the Kent surplus store.