Undated articles that have no other contextual clues as to recency should probably be avoided as references. If you have retained a print copy of the journal article, it normally will have an indication of the date of the article somewhere in the article. If it does not for some reason, you can always return to one of the library's online databases to search for the article by title or by author or by some other keyword approach. The databases as a matter of course will provide all the publishing information available on the article, which almost always includes the date of publication. Check the library's catalog for any print guides to Web sites.
Research articles are generally fairly easy to discern from more general, popular articles.
The type of publication in which an article appears is one of the first dead give-aways that an article is a research article. If so, then it most likely publishes primarily research or scholarly articles. Generally speaking, if the publication has a slick, glossy format, then it probably is not a research journal. An article that incorporates research will have a reference list and may also have footnotes. If the article's information is not documented in a reference list, it may be an opinion piece, an editorial, a narrative, a work of fiction, or it may be an overview of a topic written for popular consumption.