In addition to the good advice from Bill and Spooky Jay, Permatex anti-seize does have lubricant properties and could be used on the back side, but better to use something on the shaft itself designed for the job, like a standard spray moly or lithium lubricant (for hinges) and use the rear wiper more occasionally than you presumably have in the past to keep corrosion from building up at the aluminum-steel contact points that is presumably what allowed the shaft to seize that bad in the first place. Going for a good used one is a sensible move. You've now got nothing to lose with the old one and get carried away with heat (like Bill's MAPP suggestion, much better than a propane torch as it's a faster heat for quicker expansion to break a bond) or getting more vicious with it in a vise to see what it takes to break through the corrosion and get the shaft to move with the least amount of damage. I'm now using you as my guinea pig in case this ever happens to me.
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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now