Hi Continental,
when I did my endorsement in the late 1980's I only had an ME endorsement. I completed the endorsement and the endorsing pilot filled out the paperwork and gave me the DC-3 endorsement and tailwheel endorsement.
When I submitted the paper work to the CAA (you did not have to pay in those days.....) the clerk behind the counter wanted the endorsement form for the tailwheel aircraft as she thought that I had lost it. I told her that the twin she was putting on my licence was a tailwheel and if I was endorsed on that, it should cover me for the tailwheel. She did not believe me and had to call up stairs and speak with an Ops Inspector to confirm that the DC-3 was a tailwheel....The Ops inspector apparently told her it was the largest tailwheel currently operating in Australia.....
She obviously believed him because the licence was appropriately endorsed.
In answer to your question it is possible, but may take some time if you do not have an ME endorsement. As another poster has suggested....finding someone to allow you to do it is another question......
Fun old Bird.....I ended up with a couple of hundred hours on the aircraft......still miss those days.....cost me quite a few uniform shirts however.......lots of oil stains on them.......
Tinkicker.....