My "best guess" is a transitional case where someone has added a bevel edge at some later point, thinking that was the case ref norm. Remember transitional is a recent discovery. If you study the case pics this looks a possibility imo.

R

: Rich:

: I am told that this Autavia has no serial number . . . either
: polished off the case or never marked on it, but no serial
: number currently present on the case.

: Jeff