A CAO sticker is, for most later CAO meerschaums, the only indication. A VERY few had "CAO" carved into the pipe; why, I don't know, but some of those were not Bekler's work. The same is true for many meerschaum brands; the case sticker was the only identifier. CAO did use the brass logo dot inset in the stem, and I'm not sure when they stopped using it, but it coincided, approximately, with the new oval logo. Golden Horn and GBD also used a brass stem dot, and SMS used a gold-colored dot *inside* the resin stem, visible through the surface. In all cases, some pipes didn't have the stem logo for some reason.
Gatorlope, your capped meerschaum was made by CAO, as well as by a few other companies. The chain is often missing. I've never seen Bekler carve this design. I have only ever encountered one CAO which is unmistakably Bekler's work (abstract) but isn't signed. Your other three are, even without knowing they're signed, obviously his work. I'm still looking for one of his amazing castle pipes.