From what I've been able to find, Fender started making two-piece necks with maple boards in 1966, and continued through 1970. They went back to 1-piece with a skunk stripe in '71. Their '84 and later American Standard necks have 22 frets and I'm pretty sure they're two-piece though they also have a skunk stripe. I don't currently have one on hand, so I can't check.