First off, excellent action. GRINNING
Yes, you can have a 3 position safety installed and there are advantages to having it done. Not the least of which is being able to cycle the action with the safety on, and an easy way to field strip the bolt.
I did not have it done on mine, but now that it is done I have been considering it as an "upgrade".
Tell us some more about your build. Barrel? Stock? Optics? Who is doing it? Purpose?