Folks i am sure that this has been asked before , i looked for previous posts and did not see any , so here goes my pardner is a 2006 gun ,now question is i know from the faq that a 1999 or newer gun gun can be sent to nef to be factory fitted with a new barrel, does this mean that i CAN/CANNOT fit a say2001/2004 20ga or any ga (i know except 12/10ga ush) to my sb1 frame or even a pre 1999 to my frame?.........thankslj