Model 318 makes it a 1929 Speedster that was sold with a rudder attachment as shown. It came that way from the factory and was not an aftermarket or dealer add-on. As Tubs said, its the second motor built under that model number thus probably the first day of production for the 318.
As usual, the timer bushing is done-for, but there’s a person by the name of Dustin Greene in Loogootee Indiana who has reproduced them in aluminum and usually has some available for sale so if you look him up he can probably help you. Replacing the busing isn’t a difficult job if you have any mechanical skill.
Hint – make sure the timer cam is in place when you drill the holes for the rivets that fasten the timer bushing to the point plate.
Hope this helps
Best,
PM T2
He's livin' in his own private Idaho..... I hope to go out quietly in my sleep, like my grand-dad did..... and not screaming, like the passengers in his car...