JP15 tremolo cavity and stud through the body

I just become new owner of MusicMan JP15 guitar and this is my first post. After opening the tremolo cavity to adjust the spring so I can level the tremolo to be paralel with the body, I see one stud with screw is got trought the wood. The other one is inside the wood, pictures attached. Is that normal? Do you have that stud looking like that in your tremolo cavity?