Go the section of the manual describing cam chain replacement. Follow the directions for setting the timing. If you can get the EX on one sprocket to line up on it's mark at the same time that the IN on the other sprocket lines up on it's mark, then the chain must not be stretched.
Bear in mind that the chains will stretch, so you can miss the mark by a mm or 2 and still be within specs. Without the actual specs it's hard to say how much you can miss the mark by. But certainly not so much that you could move the sprocket an entire tooth to get it to line up. (Unless is has of coarse jumped a tooth)
Purchased new in July 2006, 0 miles.
Miles as of January 2019 102,137 miles