There are a few ways to go about it but my approach is to keep a stock of the components. The single blade your white arrow points at could be made from 3 pieces: an empty blade, a metal contact point and a plastic spacer. All of which are on this page. Let me know if you'd like a more detailed description.
http://www.pbresource.com/pfswitch.htm#common

If you want to order the blade all made up, you'll need to know which holes the contact point and plastic spacer are in, the approx diameter of the contact point, and the length of the plastic spacer.

If it is just the contact you can replace it. Carefully grind the old one off and peen a new one on.

Good point. Make sure you get the blade shiny directly underneath the point so it can make good electrical contact with the blade.

It may seem like overkill, but you can buy a whole score motor on ebay take what you need and sell the rest. If you do this, pull off some of the plastic spacers..at least one of each size just for future use.

ebay.com link: 70s Gottlieb EM Score Motor Assembly Pinball Part