Writer's Fallout Shelter

I just saw one that pays with two copies and considers payment ~ the author retains all rights to the work.

Would that generally mean that a previously published author would be paid cash, but a non-published would not be paid? I can write and ask, but don't want to appear ignorant if it's considered common knowledge (and somewhere I missed that tidbit)

Do you think it good form to submit to such a publication in order to get the designation 'published' ? Would it help with further publications if the story is accepted and published, even if not paid in cash?

Keep Writing!
Kate