Yes, you have to cut the large collar off the acerbis inserts. I also cut about 1/2" off the end of the "prongs" which spread to hold it in the handlebar. I used the TM bar ends too. When I was ready to install, I had the bolt through the bar end (with the supplied washers which let you turn the throttle lock side) through the acerbis insert into the plug which expands the insert "prongs" to afix it in the handblebar.
I also purchased longer bolts than supplied. You can get them with the same allen heads at Fastenal or online. I got some that were 1-1/2" longer than supplied. I wanted to have enough bolt protruding through the "plug" that when I loosened it to take it out, I wouldn't screw the bolt out of the "plug" and drop it down to the center of the bar. But thats just me.
I didn't tighten the assembly much and tried a few times until I got it where the TM throttle lock would actually hold the handgrip throttle where it was, but release it completely when turned to the unlock position. Putting the TM-supplied plastic insert between the grip and the bar out at the end where the throttle lock is makes it work perfectly.
A trick, if you are trial fitting like this, don't tighten the allen bolt more than a turn or two after the "plug" engages the "prongs". Then if it won't pull out, put an allen wrench or small phillips screw driver into the allen bolt head and tap it gently, this should disengage the "plug" from the "prongs" enough to let you pull it out.
Once you tighten it down firmly, good luck getting it out without popping the plug off down into your handlbar, making you take the handlebar off if you don't have the right kind of a snake.
Living the Gypsy Life