Probably nothing to this, but I recently received a local census form in the mail that used an "Official Election Mail" logo on it, probably justified because of the caption:
"Warning - Failure to respond to this mailing within 10 days may result in removal from voting list."
In any event I was comparing the cover to the official USPS Guide for use of the "Election Mail" logo and find that it varies somewhat in that the caption "Official Election Mail" is followed by a TM (trademark) logo as opposed to the USPS Guide below which shows the logo having a (R) (registered) logo after it.
https://about.usps.com/publications/pub631.pdfProbably nothing much to it, even though it represents a variance from the logo shown in USPS Publication 631.
I suppose like everything else, there are varieties of this cover that one may collect.