What is involved in making this?

[RDochert]

Yes - that was my thoughts as well. I was thinking there must some rubber washers that might do the job. However, I am going to head down the route of seeing if I can get an equivalent made before I seriously look at using washers. And thanks for advising that it was too small a job to justify using a CNC - I thought that might be the case, but I didn't know what would be involved. Lastly the only original plate I have found, for the year I need, is advertised at $180. So you are right in that respect as well.

[the great waldo]

You could try this
https://tonetechpro.com/guitar-parts...in-finish.html.
It looks like there's enough there to trim down to size. You just have to check the spacing on the main 2 screws. If you're drilling out these plates make sure you've got them well clamped down (basic metalwork!)
Cheers
Andrew