Hi Cody,
While there are some exceptions, each style of pen will require a new set of bushings. Take a look at the various vendors' websites (I like BearTooth Woods in Colorado Springs) and you will see the correlation. Hope that helps!
Garrett
Sometimes one pen does use the same bushings as another but there are very few crossovers. I always get dedicated bushings for each style whether I can use another or not. Just safer to know they work. I even have bushings for different vendors of the same style. Overkill, I guess.
Take a look at this and it will give you an idea of the variety of bushings as well as tubes and pens. It is also a great reference to have on hand in your shop. You can find all kinds of good info like this in the IAP library.
You can use the bushings from a slimline as long as the diameter of the finished pen is equal to or greater than the diameter of the bushings, and uses the same tube size. It just takes using calipers and checking the diameter of the pen fittings and turning to the same diameter. It's a good habit to get into even if you have the correct bushings.