The opening date (a new PO from scratch, see below) and closing date as well as postmaster Weidemann all match the information published in the daily Postal Bulletins at this site:http://www.uspostalbulletins.com/
As for a "Five Points" connection. Jim Forte's Postal History website has an extremely good list of US post offices and does not list a Five Points office in Iowa, so it appears there was NO renaming to be done. Perhaps this was merely a local moniker for the crossroads community. And indeed that appears to be the case. I note the opening and closing Postal Bulletin announcements state that the mail to Lapage will be supplied from Rickardsville, and when the office closed the mail went back to be handled through Rickardsville.
Additionally, Guy Reed Ramsey's book "Postmarked Iowa" does not list a Five Points among the Dubuque county offices. Ramsey lists the exact location of Lapage as "unknown". Fortunately, using the idea of being near Rickardsville from the Postal Bulletins and the Dubuque county map (date unknown) in Ramsey's book, sure enough there is a "Five Points" 2.5 miles SSE of Rickardsville (and about 4 miles north of Graf, Iowa). To attempt to pinpoint more exactly where the Lapage PO was in (or very near) Five Points, I would recommend:
The USPOD also has "site location" records which are copies of the applications for new post offices and additional periodic returns from time to time. These are arranged by county. Each form should contain a locally-drawn map showing the office of interest and the other nearby offices so that one can often find your town of interest mapped into the reports for the other nearby towns too. https://www.archives.gov/research/p...37-1950.html
Finding a cover for such a short-term office will be extremely challenging.