Pretty much, yes. Unfortunately a consistent UI wasn't designed for
ACS 3.x. It was added along and many of the modules had their own. In
the OpenACS getting started guide we list some things you can do to
customize appearance, but there is not a way that works for all the
modules.
The ad_header way works for a bunch of them. For the modules that are
templated (e-commerce, SDM, news, polls) you can use the templates system.
This is fixed in OpenACS 4.x of course (which is not released yet).
