Yes, nearly all Beklers from approximately 1974 until his retirement were signed. His earliest imported pipes, via Royal Meerschaum, were not signed, but were accompanied by a tag. However, I've seen a handful of pipes that were most definitely his work, but were not signed. These I've IDed were mainly abstracts; nobody carved abstracts like Bekler, and once you've seen twenty or so and handled a few (and especially if you've also seen his relative Kural's abstracts, which are also distinctive) you can look at one and 'know.' All of these I've seen were made during the CAO era.
The pipes carved with a date and "CAO" seem to have been done in the very early 1980s, and I haven't seen any rhyme or reason as to why this was done. Some have "(copyright symbol) CAO," with or without a date. Some I've seen with dates, I doubt were Bekler's. Bekler's limited editions were also almost always dated, signed and titled, with a few having "CAO" etc. too (I say "almost" here because I have a pipe which is unmistakably Bekler's, and definitely from his abstract "a la Rodin" series' from 1980, 1981 and 1982, but is unsigned).
Is this in a local shop, or online, or what? What kind of carving is it? Do you have any photos?