As promised you can find scans from "Joy of Soaring" (1969) of the
BJ-4 here = http://aviation.derosaweb.net/images/BJ-4/

If the wings of the BJ-3 were used on the BJ-4 (they sure don't look
the same in the two images) then the fowler flabs shown on the BJ-3
are removed on the BJ-4 image shown in the "Joy of Soaring" - which
would explain why I am seeing the 3"-4" somethings (hinges?) hanging
off the trailing edge.

Frank - Where on http://sailplanedirectory.com are you finding that
information? I cannot find.

Interesting ship.

- John