Yep it's boneyard time for you unfortunately. Hopefully you can get a pre-pulled one for a little bit more cash, but it will be worth it in the end because as Jorell said, this is a total P.I.T.A. job that takes a good couple of hours-even longer if it's rusty. You might want to bleed the brakes as well just to make sure there isn't any air in the lines. I wish I had a bike right now as my '87 is driving very unreliably, and I don't have a job to get a new fuel pump relay for my '88 which is why I'm flooding the brickboard posts with my comments because I have nothing else better to do haha...Well good luck with the booster, like Jorell and I mentioned, this is a real P.I.T.A. job but it's quite satisfying when the job is done.
-Eric