Vintage BMW Motorcycle Owners

I was hoping some of the resident experts could assist me with this 84 r80 gs gearbox input shaft. It does not appear that this gearbox has ever been apart, motorcycle was purchased not running and last registered in 05. These do not look like the proper mating parts on the cush segment, and also as an 84 this should be stamped with "X". Has anyone seen this before? In the absence of any spare input shaft assemblies I'm at a loss for what to purchase to make it right. Thank you in advance for your time and attention. Bill

Pictured on the right is the drive out of my 84RS. On the left is the drive that came out of my 93 RT. An ear broke off the drive gear on my RS causing it ride over the ramp if I was in a gear higher than third. The drive out of the 84 is not marked with an X, the 93 is. You can see the new part is made stronger. The wear pattern from your picture makes me think it was manufactured wrong…it happens. I don’t see how it could be put together incorrectly. The transmission pictured in pieces is the 93.