You are not permitted to 3D Print parts (there isn’t specified in rule r7, read the game manual).
Our sister teams have successfully a) filed down spacers to the same size (or roughly) the same size as the ones used in this video, b) purchased similar sized ones from a local store (I think they had to drill down the center since the screw wouldn’t fit).
If you’re looking at the dimensions, inner diameter is .194" (so an 8-32 screw can fit through) and the outer diameter is ~.200", from what I’ve been able to get. (They’re extremely thin)