Welcome to the forum, snicker.
If it's all basically working fine, you may well have nabbed yourself a good'un. The 4480 dates from 1967 and, looking at the details in Blue Book, it does look more or less like a full console version of the 4140 spinet (1965). Nothing really special about it, a pretty standard console organ of the era. Theatre voiced, but with a straight console. Horseshoe consoles cost extra! Free is normal these days, there's just so little demand for old organs that many are given away. Consoles can hold a bit of value, expecially for those wishing to gut them and use them as driver consoles for virtual organs. But, having said that, their size puts some potential buyers off.
That lone faulty F# sounds like it could be just a key contact. Other things to check out are power supply capacitors, which really should be changed if they haven't been already. In fact, go over the whole power supply and associated wiring. If the AC cord is old or brittle, change it. All this is for safety, of course. The Spectratone belt can stretch and start slipping, so that may also need replacing. As well as Morelock's, there's also Organ Service Corporation and W D Greenhill for spares, manuals etc.