> That tells the server version running, but does it tell the initdb
> binary version used to init the cluster?
Normally there's not any difference between dot-release initdb's.
In this case there is; read the 8.0.3 release notes:
http://developer.postgresql.org/docs/postgres/release.html#RELEASE-8-0-3
You could determine which was used by looking at the declared arguments
of the conversion functions.
regards, tom lane