As an ex Tech Author, who used to write aircraft service bulletins, I can say that the ones I wrote included c/n's, which made for no doubt as to which aircraft the bulletin was applicable.
As someone previously eluded to, if the bulletin says all BAe146 aircraft and yours is an RJ type, the SB does NOT apply to you. All of the mandatory SB's would have been incorporated prior to certification as an RJ series aircraft unless the item/system/whatever had been changed beforehand.