I've seen so many different versions of both "Enardoe" and "Deland" decks since we looked at the vintage one (Deland) I bought in a Steamboat #220 tuck, and I found a vintage Enardoe "Double-backs" deck on eBay this evening for $4 - mint, sealed and vintage 1940's maybe early 50's (blue). There seem to be quite a few varieties even 'new' now, like a "Haunted" deck, "Force" deck, "Blank faces" deck, "Cheek to Cheek" deck - all Enardoe, but apparently contemporary and not vintage. I'm supposing someone bought the rights to reproduce them and is churning them out like french fries. Most are in the $5-$7 range but I've seen quite a few listed in the $20-$23 range on eBay and Amazon. Curious... I'll have to take some pictures when it comes in, but I'm 99% certain that it is a mint 1945 - 1950's deck, possibly earlier. The Deland "automatic" or "$100 deck" is easy to find, maybe $5-$7 as well brand new, but they are now made in China vice USPC Co.
The Deland "Nifty" I have is definitely somewhere around the 1930's or maybe earlier, per Hochman's could be early 20's as I recall (I'm not looking at it nor my notes). The instructions for the "Automatic" or "$100 deck" (clockwork based) are easy to find, the other 4 that I've found aren't. I've just about decoded the Nifty, and as I noted once I'm certain I have it exact I'll cobble up a PDF file in Acrobat.