Well have a good old read of the haynes book, see if it mentions the auto advance, a giveaway will be if you can twist the points cam back and forth, that will mean it does have one (unless its siezed up, then you might not be able to tell)
anyway i'm sure there will be a pic in the haynes book, basically all it does is throw some bob weights outward as the engine speed increases, in turn the movement of these weights turns the points cam which advances the ignition timing. as revs fall springs pull the weights back in and the timing retards again.
is that clear