RZ350 Crankcase Unknown Part

[willno1]

I'm in the process of restoring an 85 RZ350 basket case that's missing a lot of parts. While looking at the parts diagram for the crankcase I noticed a part called a "collar" (Part # 48H-15337-00-00). It doesn't look like a collar, it looks like a flat plate or cut out part. It's no longer available and is only on the 85 and not the 84 RZ350. I can't find any info on this part. Anyone know what it is and if I need it?
Thanks

[tacky1]

It’s not needed. It’s just a noise damper

[willno1]

Thanks tacky1.