What are your thoughts on taking it apart to (hopefully) clean up the 'innards' vs. leaving it as-is...where the driveshaft is 'locked'? Being a loyal 'Antiques Roadshow' fan, I know that in most of those cases, the answer is always 'LEAVE IT ALONE'.
But something tells me that maybe in this case, maybe purchasers would shy away if they're not certain it's repairable. There's no corrosion/rust, so it's gotta be locked-up because it's gummed up with old castor or something, which I'd think would be pretty easy to clean up w/the right solvent (which one?).
So whaddya think...would the buyer prefer to fix it themselves & not risk having a novice mess it up while trying to fix it, or would they shy away unless they know things are at least spinning freely? And I'm pretty sure he'd open it up to clean & lube it...and check to see if the cylinder head protrusion was filed down like the service bulletin advises owners to do. And let me know if you/anyone wants to see a scan of bulletin...I'm thinking a LOT of 1960-model owners would love to see that, as most of them probby never even noticed the problem & thus never got the bulletin!
MY OPINION: I never even think about the thoughts of eBay bidders. I have never been able to fruitfully predict what they will buy and don't buy. I have one rule for my own selling and that is to provide as much truthful information as I can about what I am offering for sell.
If I feel the need I will put a reserve price on the item.
One thing I do have some fun with is these "smart alecs" that have access to several computers each with a different account and they will keep bidding THEIR item up thinking a bidder that is bidding up will continue to do so. I like to get them up to the last minute and then not bid again. Several times I have found the item relisted after they find themselves the top bidder.
I play honestly and expect same unless I find someone trying to hose me.
So if you have concerns, then do as you please however if you say it is a long time in storage, and feels gummed up, you keep the unknowing from buying and the Collector doesn't mind as he knows what to do about that. Collectors can make them like new in a short period. That is their hobby.
If you must, then load it up with any good Penetrating Oil and let set for a day or so. Then keep playing with it until the bearings give, by using a LONG prop and trying to turn it over. Once it starts keep applying oil, then wash it out with 90% rubbing alcohol. Get it dry and reoil. That should last several months if kept indoors.
OOPs just saw icerinkdad's input. That sounds better than mine.