A good thing to do with the vintage adjustables is to give them a good long soak in hot tap water with some washing up liquid added. Allow the water to cool and leave it soaking overnight. Maybe repeat this a few times. You'll be surprised at the amount of crap that will have found its way into the inner workings of these over the years and this is a good way of loosening it up without damaging the razor finish or removing the paint from the numbers.
You could consider having it replated so it looks like new, Dave at safetyrazors.co.uk charged £15 to replate my Fatboy.