scribe it and inlay oak
then temporary set up the railing for hole placements
pre - drill slightly smaller holes and then screw "tap them"
create threads .........yes in wood
install those 1/2 screw / half bolt studs
and then glue turn them in
use cap style nuts on the threaded end
to hold the railing on
inlay (if it was me in those circumstances)
Threaded Mode