It depends on how it's finished. You could take it apart and do something to it but I doubt it would look like one where you start with a fresh piece of leather.
You could, however, incise it successfully. If it's a Slimjim, that could look pretty cool. That would be easier done taken apart but I seem to recall many originals were done by the owners after they bought them.
![](https://i.imgur.com/O69GmyT.jpg)
As an option for you to consider, perhaps a concho or two with a blood knot would give the guy some pleasing embellishment(s).
![](https://i.imgur.com/R2xaY9y.jpg)
Spots are another way to dress one up. You would want to put them where they wouldn't scratch the pistol.
![](https://i.imgur.com/fpl1EjC.jpg)