This is a 0.75 inch post. It is a fine replacement. It locks in tight, tight, tight and make the plastics hold together really well.The body is round, rather than having a cruciform cross section like the Williams part. I did find the Williams part, but the samples I received were yellowed. Furthermore, only the 0.5 inch version is stocked.

These 0.5 inch posts are .03 too short compared to the originals, but they look just fine. My main concern is that the plastic sits level, and from the photo all is well.

I have replaced the rivets with 3mm hex head stainless steel screws. The polished rivets look sharper, but the screws can be installed in place. I had to remove the rivets for plating. I'll put rivets back if/when I get the playfield clearcoated. Or maybe when I figure out how to rivet.

I also have some nickel-plated hex standoffs of the right size, that will take a screw at the bottom and a locknut on  the top. That's for later.

1/2 inch Mouser P/N 534-1946.

3/4 inc Mouser P/N 534-1948