Lol, no it isn't. After trying to screw the counter weight shaft in (with and without adapter) and finding no threads, I put a flashlight on it and used a small screwdriver to probe the bottom. Smooth sides all the way down.
Interesting as Skywatcher have said that the mount is not for AP and that generally means equitorial.
After they brought the mount out they added in one of the updates the Eq mode, that was not originally included. People squeeked and they thought it a good idea, but SW have maintained it is not an AP/Eq mount.
In the Eq mode you do need a counter weight so there is the possibility that SW have decided to not thread the hole and so prevent people using the mount for AP/Eq, by effectively removing the Eq counter weight ability.
Will be interesting to see what is said here by one or two retailers.
However if you cannot add a counterweight then why have the hole, would have thought it easier to put a solid cap in.
I can understand SW in a way as once people think it is OK for AP they expect more functions and greater accuracy and more features. And the mount is a small fairly simple Alt/Az mount.