The following bug has been logged on the website:
Bug reference: 7712
Logged by: François Bonzon
Email address: francois(dot)bonzon(at)gmail(dot)com
PostgreSQL version: 9.2.1
Operating system: Ubuntu 12.04
Description:
This header is an optional feature of .DBF files to specify the character
encoding of its text attributes (UTF-8, CP1251, etc.). So is a .cpg sibling
file, that can carry the same information, and an alternate way to store
this information, that many GIS software support.
The dumper tool pgsql2shp should set this header, as PostreSQL knowns what
encoding it is writing to.
Some popular tools (including OGR library, QGIS) are mis-interpreting the
encoding of a shapefile that is missing this header.