I'd check frequently, or put a saved search on ebay, if I were you. Case Construction still handles them in hard copy, and PDF, but price is $329.09.
I did come across a supposed free PDF download, but requires you to download Google Chrome to do so. Got a lot of hits, using the manuals item number,
Item Number: 9-99774. Put it in quotation marks if doing a search, and it will pretty much search for that item.