Sorry, Stimpy, but there's not any real ryhme or reason to figuring out when and what a barrel is by year of mfr, they started the fluted barrels with a 1:9", then switched back mid year 2005, then said all 2006 barrels would be 1:9", then didn't, or did then switched back. And as you said, someone posted that they had switched back to 1:12" permanently.
Soooooo, the only way to know whatcha have is to check it with a cleaning rod and jag, info in the FAQs will show how, H&R doesn't even know what barrels are which!!
Tim