Here are some pictures for you. The first shows a set of GMC strikers and hardware (I believe these were ‘52 or 53), it seemed the became more numerous as time went on?
https://www.flickr.com/photos/advance-design_parts_co/34221115271/in/album-72157631868452754/
The previous versions 1947-50 were much thicker, two per side.
https://www.flickr.com/photos/advance-design_parts_co/13043938893/in/album-72157631868452754/
Here are some NOS shims used for spacing adjustment. I can not recommend strongly enough the use of NOS parts if possible, reproduction latches and strikers are in my experience of poor quality. NOS originals are available frequently on eBay, original hardware installations are now some 6-7 decades old!
https://www.flickr.com/photos/advance-design_parts_co/25797047532/in/album-72157631868452754/
https://www.flickr.com/photos/advance-design_parts_co/16577213489/in/album-72157631868452754/
https://www.flickr.com/photos/advance-design_parts_co/8129483247/in/album-72157631868452754/
Thin striker locks/spacer detail.
https://www.flickr.com/photos/advance-design_parts_co/38126865774/in/album-72157631868452754/
You might try an ad in the Swap Meet for a replacement.