8.3.0 upgrade

I just finished upgrading my production DB to 8.3.0. Everything went
smoothly, but I thought of a few questions.

After the upgrade, while restoring my backup to the new version,
I got this error message:

ERROR: role "postgres" already exists

I assume this is nothing to be concerned about. But is there something
I could have done to avoid this error? (I think I followed the upgrade
instructions to the letter). Is there any scenario where the "postgres"
role wouldn't exist? (should pg_dumpall exclude it?)

Moving on... In step 6 of the upgrade instructions, it says:

"Restore your previous pg_hba.conf and any postgresql.conf modifications."

Perhaps this should also mention pg_ident.conf since I restored the
two mentioned files, but still couldn't connect. The third completely
escaped my mind until I ran a "diff" on the old & new data directories.

Next, one of my apps failed because of a dependency on libpq.so.4.
During previous upgrades, I remedied that by installing this package:

compat-postgresql-libs-4-2PGDG.rhel4

But it seems under the 8.3.0 binary downloads, this package is no longer
available. The only compat package is "compat-postgresql-libs-3"
which of course includes only libpq.so.3 so I had to browse older
releases to find the missing version which I thought seemed a little odd.
Am I missing something?

Finally, regarding the new "HOT" feature. The release notes say that
benefits are realized "if no changes are made to indexed columns".
If my updates include *all columns* (the SQL is generated dynamically)
but the new value matches the old value for all *indexed* columns,
do I still reap the benefits of HOT?

Thanks!

Adam