When I made my gin pole, I made it with a large timber base, like an upside down T with braces:
This way the bottom is heavy and some what stable from left to right. And it provides a lot of surface area to bear on the ground/frame deck, if erected inside the frame. I learned this from Jack Sobon, and also saw it in a book by Richard Babcock.
If you aren't going to make yours with a large base then yes, you have to secure the base so that it won't slide out on you when you raise it.
