Then it's a very good question: If you have a type rating in an aircraft with a tailwheel, do you =also= need the endorsement?
A strict reading of 61.31 would seem to suggest that you do. And, although it doesn't deal with tailwheels in particular, the language in Paragraph 4b of AC 61-89E, "Pilot Certificates: Aircraft Type Ratings", suggests that at the time of your DC3 type rating, you should have =also= received a tailwheel endorsement:
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Most airplanes that require type ratings have more than 200 horsepower (or the equivalent thrust), pressurization, and service ceilings and/or maximum operating altitudes above 25,000 feet mean sea level. Pilots would therefore be required to receive both a high-performance endorsement and a high-altitude endorsement in their logbook or training record before acting as pilot in command of those airplanes. If they do not have the endorsements when they begin training for the type rating, the training for those endorsements may be included in the type rating curriculum if the airplane for which the type rating is required fits the appropriate description. However, separate logbook or training record endorsements must be issued for the type rating, high-performance, and/or high-altitude training, as appropriate.
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Hows that for absurdity? Sounds like technically you can't act as PIC in the aircraft you're type rated for!!