You do not need to "program" the battery unless you get a battery with different specs (cca) etc..
Registering the battery just resets the charging system to charge less vs charge more on a new battery.
If you have an old and weak battery, the charging system charges harder to keep the battery charged. Dropping a new battery in without registering it, the system will continue charging the new battery as if the old one was still in there. The worse that can really happen that I know of is, the new battery will not live out it's life to it's full potential from always being over charged