Quoted from Tsskinne:
I did not install one in my first scratch build Star Gazer two years ago, and looking through the Star Gazer thread it does seem that some games have it and some don't.
Interesting, my Stars machine occasionally “gifts” the player with a grace ball after the drain, never put it together that that post was there to mitigate that tendency.
On my other machines that have the post, I like to use a standard post with rubber sleeve, just to have one less metal-to-metal contact point in the game. This has the odd “advantage” of occasionally facilitating an accidental bang back if the ball is going fast and you keep the flipper up. To me it’s a bug that I’m calling a feature, makes the game a little wilder and more unpredictable.
The guy you sold the game to should be cool with not having the post, it isn’t essential for the game to work, and if they want it there, it’s super easy to install - but of course I never trust people with those sort of operations, so maybe it would behoove you to go install it for him if that’s an option. It isn’t like you were choosing to cut a corner but if it makes them happier I’d just do it, it’s an understandable oversight and an easy enough thing to address.