Hi John,
That letter in reference to Odin International's request for a ruling only pertains to Odin International, technically. Legal rulings are only specific to the individual or organization that makes the inquiry to Tech Branch. That said, they are often taken as a blanket authorization for other filers of a Form 1 to emulate.
In any event, you'll notice that this is only germane to two pistols mentioned... the Luger & the Hi Power. Missing is any reference to the Chinese or German broomhandle. This is covered & unchanged in the C&R listing on the BATFE site:
http://www.atf.treas.gov/firearms/curios/sec3.htm
I am aware that certain pistols are exempt from NFA purview when equipped with a repro stock, but the broomhandle is NOT one of them.
The ATF even reversed its decision on the Browning Inglis Hi Power pistol at a later date ('99) in this ruling/advisory:
http://www.cs.cmu.edu/afs/cs/user/wb...f_letter70.txt
I would suggest that anyone considering the installation of a repro stock on a broomhandle pistol to 1st obtain a specific ruling to that effect. Assumption based on unsupportable documentation can be a very costly mistake!
John