Yah, its necessary. u need to hand in the FFI form to get your
pink IC. Plus must fill in some other paperwork/clearance
forms.
For my experience, i had to book it myself. I had to go to Selarang
to do my FFI b'cos my camp's medical centre not equipped for dental
check. Called up Selarang's MC to book appointment. The medics
there knew the procedure.
It was all OTOT, did it a couple of months before ORD.
But i not from Army, so i dunno if yur procedure will be the same

For yur case, since medical corp already located at yur camp, can
juz do it there i guess.