the "2" means it was made in 1962 (or at least the serial # was assigned to the receiver then). the "X" means it's a medallion grade. per eastman's book, 1962 was the first year the medallion and olympian grades were offered but he's at least partly wrong in that as i owned an olympian grade that was dated 1961. but i've also owned a couple of BAR's in higher grades that were also dated a year prior to when he claims they were available.
that gun will by default be a long extractor and not a chance of salt, i.e. one of the most desireable, particularly in a big magnum. the initial shield wouldn't be original to the gun unless someone ordered it that way. unlikely but no way to prove either way unless there were some authenticating paperwork with it.
roger
