How big of a job is that? Other comments?
For most purposes in OpenACS oids are not needed. A quick grep returned the following places:
The config flag
default_with_oids is just used for creation of new tables. So if one migrates an existing database to e.g. PG 9*, the oids are as well migrated, and one does not need the flag in the config file.
I am not sure that pg wants to get rid of OIDs, since these are used as PKs for various system tables (see datatype-oid).
For new installations, if the goal is to remove the config dependency, the simplest fix is probably to add
WITH OIDS to the few tables, that still require OIDs.