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Assuming nothing changed, and if Discover pulled a FICO, then it's always possible they pulled a CC-enhanced FICO, or used a newer version of the Classic score from here.
Yes, though I've found most CSRs wrong or unknowledgable. Aside from that, look within these forums. Some post this same or similar question, even about Discover. You might find someone else's post about their score in relation to their last known pull. Also, look at the letter itself. Sometimes the CCC will list a score range and that'll give you an idea about the score.