Yes, the screw holding the teak rubrail are countersunk and hidden under the stainless strip. Take the strips off and you'll spot them. They're shockingly long screws, so make sure you get the exactly right screwdriver/bit and carefully undo them - some torque is needed but none snapped off, I even managed to get the bent ones out (removed rubrail after a little incident with a badly designed fuel quay).
The stanchion stud will come out if you remove the stanchion from the top, then stick a pin in the screw hole on the stud and turn it counter-clockwise. It's bedded in (failing) sealant and threaded along the entire length, so it will slowly screw out that way. Easier than trying to hammer it out from below and you won't risk damaging the threads.
On the Ocean series toerail, I had to undo and rebed all of the stanchion studs as well as the mooring cleats, as most were leaking.