just to toss in my 2 cents worth , if the wood is 1" thick and not T & G , it's not regular wood flooring ,but it should still work. i assume you will be sanding the floor smooth (if not now some time in the future) so how you fix it to the floor is the question. you can't face nail and then sand,so i think you should pre-drill each piece (counter sink) then use a plug,thats how they used to do it ( with dowels) good luck

directly over 2X12's or over a subfloor.. you should use a subfloor, or it will have a greater tendency to "cup" no matter how you install it. I'd face nail and plug, but I'd also glue it with Bostiks best adhesive, wide boards always cup no matter how you install them..

Oh, and alot of Antique flooring was 1" thick or greater and had no T&G.. sounds like what you may have. (my 2 cents worth) hehe..good luck