It looks like you have a U277 stamped envelope (1884-86 series, which did include Watermark 82) and the 1932 1-cent stamps were merely added at the time of posting.
Seeing as the year is illegible in the postmark, the 4-cent first class rate was in effect from August 1, 1958 through January 6, 1963, so I suspect the date of use was somewhere within that period.
Since the U277 stamped envelope is not particularly valuable at $1 (2013 SCV), the best guess scenario is someone had the envelope laying around and decided to use it many years later, probably by a stamp collector.
This is further supported by the fact that the addressee of the cover, H.P. Boyce (a/k/a H. Prescott Boyce) was a noted stamp collector back in his day:
Posted 01/19/2015 8:31 pm
