While I don't remember the exact source, I seem to remember the ATF saying that they would not ban or declare the Saiga 12 a DD based soley on aftermarket accessories. As I understand it, guns like the Stryker 12 were ruled destructive devices not because of aftermarket parts, but rather because they were never offered in a "sporting" configuration to begin with.
Smith, and Wesson, and Me. -H. Callahan
Well waddaya know, one buwwet weft! -E. Fudd
All bad precedents begin as justifiable measures. -J. Caesar