Hi Dan,
Sorry for the silence on this question -- I'm not sure, but it could be that no one here knows the answer. Production data is hard to find in a lot of cases -- we could probably find out how many C-60's were built by month, by location, but beyond that may be difficult. I do not think your Scenario A above is valid, though -- the 261 seems to have well withstood the test of time to become a highly sought after engine.
Maybe one of our resident gurus will tell us more. What else can you tell us about your truck? Any pictures you can share?
Thanks,
John