My Type R shift knob didn't come with anything except the knob, a nut, and a flange. The instructions I saw here said something about having to take the whole thing apart and put another adapter on it, but the stock one works just fine.
You should be able to just use the stock adapter as long as you have the rest of the hardware.
Speaking of shift nobs. Remember those cool Spoon shift nobs that were in that clearance thing on ClubRSX? Do they even exist anymore? I was going to get one but then they were gone. They had them for both 6 and 5 Speed. They were an aluminum color with red numbers. Thanks.