Perpendicular H - P would be used ~25000-110000 (read "properly" if the barrel is held with chamber on left, muzzle on right)
>> close enough to 23xxx for gov't work. <<
Inline H - P would be used 110001-425000 (letters read properly if barrel is held with chamber closest to you and muzzle furthest)
I think there's enough uncertainly/leeway in actual assembly dates that it's probably ok.
I wouldn't sweat it unless the wear patterns on barrel and frame are completely different indicating it isn't the original barrel.