If a truss rod fits pretty snug in its slot, can the fretboard be put on top without having the truss rod glued in?
What style trussrod are you using? I know for double action type rods, and I think all other rods you are NOT supposed to glue them into the slot. So yes it will work fine unglued, unless it is some type of rod I am not familiar with.
For the hot rod just cut the slot the proper width depth and length. It is actually recomended that you cover the truss rod with tape when applying glue to glue the finger board on. For this kind of thing glue on the trussrod is not a good thing.
The Hot Rod comes with an info sheet that you should read. They recommend using something like a silicone tub sealer to keep the truss rod from moving or rattling.
Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products. Browser not compatible