Looks like you're ahead of the curve, damn academics
... Check with Wefco Rubber Mfg in Canoga Park re. rub rails. Try Wefcorubber.com.
Oh, yeah, if you haven't yet taken delivery on the motor you might consider replacing the transom or at least raising it to take a 25" shaft motor.
Caring for classics like those Shields I guessing you're far more savvy with maintenance than most...
