You mean it doesn't come with T-molding? That is crazy.
Anyways, you can put T-molding on at the very end if you choose to.
I have an Ultimate Arcade II cab and yeah, I was a bit upset that the T-molding wasn't included. It does state on their site that it's an 'extra', but for some reason it didn't jump out at me that it wasn't included. I guess I thought a different color than black was 'extra'.
Their prices on T-molding isn't bad, but when you consider the price of the cab kit, it really should be included. Shipping wasn't the best experience either... it took a week and a half to get the T-molding even though they processed my order immediately and sent an email the same day saying it was being sent. It wasn't actually shipped for several days.
They recommend installing the T-molding before you put the top on because the T-molding is actually slightly wider than the wood. I can say it's not a problem installing the T-molding after the two pieces are put together.
... And everyone is right, this is the easiest part of the project. Make sure you have a rubber hammer to tap it in. You can 'press' it in but you won't get it all the way in and it can look a bit bumpy. I light tap and you're done.