Looks good, HD. I love the look of (red) cedar myself, which is good since it's the most common around here. Sapwood generally isn't great structurally, but in a showcase piece like you've done the contrast is really striking.
Cedar's pretty soft though so I'd treat it for sure. I haven't used it for scales, but I have used it for file handles because it's soft enough that you can jam the rat tail into it without it splitting (with predrilling though) and it's soft enough that it only takes a few minutes to shape it.
You can make it a little more durable by treating it with a product called CPES (clear penetrating epoxy sealer). It should be easy to find in a hardware store if you look for liquid (not paste) rot repair formulations. Sorta like down-and-dirty home stabilizing...
Just be sure to get the natural oils off the surface so it'll be able to penetrate. A wipe with acetone will do it. If you warm the wood as well, the pores will open and the epoxy will penetrate better.
It's definitely a 'duct tape and bubblegum' approach to rot restoration but ideal for this sort of thing.
IMHO of course.