I'd hate to see this go unanswered, but I don't know exactly what the deal is with the part numbers. You could always buy the one you think is right locally, and return it if it doesn't fit. (or buy both part numbers, and return the one that doesn't fit)
I don't use CAPS, so can't help you there.. but my DSM manual on CD should arrive in a few weeks
And I have access to the Mitchell system as well. Good luck