Ooh, I think I might have misunderstood this, does the config imply whats already in the map in terms of legit props and illegit ones? If you can do something different with the less popular maps / less played maps then maybe they could be rejuvenated through tweaking (not only with props if opportunities present themselves eg resizing the playable areas etc, but that is a lot of work
It depends what type of config they're talking about.
The PROP HUNT config is the ban list for weapons and classes, class limits, and weapon attributes.
The MAP config - which is different for each map - describes how long the round time is and what props are available to hide as through spawning.
As far as I know - since I have never had access to it - the PROP MENU allows you to hide as any prop outlined in the map's config plus a few others, the CP, Lil Chew Chew, HHHH, sentry, ghost, etc. The prop menu specific props are available on every map.