I was an ME beta tester. My final CD has version 5.50.4134.0100. Go figure. I think "4134" refers to the day that the build was compiled. For those who don't know, code development at MS is a 24-hour processes. Programmers work during the day and a new build is compiled every night.
Anyway, since Print Preview and 5.01 security updates are likely the only new features of 5.5, I doubt any one of us will have much more than someone else.
-SUO