Positive sign is I've just came across a thread via a picture on Google pics, which references the same sizes for brake calipers on a Nissan 300z
https://z31performance.com/forum/z31-repairs-forums/engine-mechanical/8685-rear-caliper-e-brake-bearing-fixed-updated-pics
Im doing mine at the moment lol
could you not use a piece of brass plate and bend it around the pin to shape it. It’s not a proper fix but will last alot longer than plastic mate