I would do some light lacquer finish. I use nitro, not water-based, since one experienced luthier said " Never use anything with word "water" on guitars, especially necks!" I don't know how this rule works on guitar bodies, but that seems to be true to the necks.
Here is the simple schedule I used on my Warmoth 59' LP mahagony neck :
1. Fill in the grain to make the neck smooth.
2. Apply some stain, I used amber stain to enhance the mahagony's natural texture.
- You can change the order of steps 1 and 2, it depends on the result you want, if you want to outline the grain do the stain first and grain filling next.
3. Seal with 1-2 light coats of sealer, I used Behlen vynil sealer.
4. 2-3 final clear coats of nitro lacquer, satin or gloss - it's up to you.
5. Two weeks to cure. Optimal for me to be sure that the finish is hard enough to be sanded and buffed.
6. Final wet sending up to 800 grit + buffing.
Result - light and smooth finish, enough solid and reliable.
If you have binding mask it while staining and grain filling, unmask for the rest of the finishing.
Don't forget to send between the steps/coats starting from 220 up to 400 or higher grit.
I would not recommend to leave it unfinished since mahagony tends to become dirty and darker after some time.