I think it is possible to make a distinction, but there is likely going to be some overlap:
- publication would cover questions such as, when a specific book was published, in what form or what type of edition, possibly in what year and by whom (typically for older works, when there is some uncertainty), in other words how a publication came into existence as a publication (which involves a publisher), not as a text (which usually does not involve a publisher).
- publishing would cover publishing practices in a specific place (city, country, ...) and era. Questions with this tag would mention specific works only as examples.
Since publishing practices always affect the way a certain work was turned into a publication, there will be some overlap. For example, Why weren't Blake's poems published in their original painted form? is both about the original publication and about publishing practices, so both tags would be relevant here.
In the question What does “Printed for…” mean?, the example cited in the question is merely illustrative, so only the publishing tag is appropriate here.
Questions tagged publication are about whether certain works ever got published, when they were published, etcetera. The publishing tag, as defined above, would not be appropriate here. (Exception: Why don't the modern printings of Campion novels use the original artwork? should be tagged publishing based on the above definitions.)
Below are draft tag wiki excerpts for the two tags:
Questions about current or historical practices in publishing that affected or would affect many or most publications in a specific period and/or place (country, city, ...). In this type of questions, specific works may be cited as examples. However, for questions concerning the publication of specific works, use the [publication] tag.
Questions about the publication of a work, not the text of the work itself. This type of questions asks about how a specific text came into existence as a publication (which involves a publisher), not as a text (which usually does not involve a publisher. Valid examples are when or in what form a specific work was published and by whom. For publishing practices of a specific country or time period, use the [publishing] tag.