Welcome to the forum Drifters. I've built an IB-5 and love it. I've fairly recently converted it to a fretless and love it. Still need to file the bone nut down a bit.
Start a build diary when it arrives. Ask any questions you have. Do a mock build. You may want to do a few modifications. The control plate isn't recessed so I recommend you recess it. Also the output jack you may have to modify the cavity a bit so you can get the nut to reach the thread.