Which clutch for an XL-12?

[jlsassoc]

I have two XL-12s and a super XL that I like to keep running. Serial numbers are 69222279 and 23181760 for the XL-12s and 2995753 for the super XL. First, are parts interchangeable for these saws? Second, my XL-12 manual shows the clutch assembly as A-69480-B. I have found a new assembly with a number A-69480-C,...what's the difference and will the "C" part work? Third, what is the difference between Wico and Phelon parts,...the manual says they are not interchangeable. Which do I use?
Thanks
JMS