You're not the first to get inaccurate info from Madison CS, unless they've changed their policy in the last month which I'm checking on right now, they will not fit any rifle barrels to '96-'99 SB2 frames, we first learned that from a member that sent his frame in for a 45-70 barrel which they wouldn't fit, I have confirmed that policy with an H&R representative that I've been working with for over 2yrs now, I haven't got any details as yet if they'll fit any barrels to those frames, shotgun or rifle, but since the 45-70 is a low pressure barrel (it's not marked with an asterisk *) there's not much chance they'll fit anything but possibly a 357 or 44mag barrel to them or shotgun barrels, but that's just a guess on my part.
Tim