It's worth mentioning that a lot of Gottlieb EMs will have different scoring depending on whether you set them to 3 ball or 5 ball. I find the 3 ball scoring tends to be a little unbalanced (like for instance 1000 point pop bumpers on Royal Flush) so most every EM I've owned I've set to 5 ball.
Anything SS or later 3 ball all the way.