The item on the web site is a filler for the complete hidden winch assembly which includes a cradle for the winch and all the mounting braces and brackets to support the hood latch and headlights. The Price point of $600 is HIGH but will come down as soon as the prototype is complete and I receive my billing. I would rather drop the price then raise it later.
The Winch Plate is as you pointed out is just a piece of metal that is shaped and has mounting holes, It is MUCH less but I have to contact the fabricator who has the plans in his water jet computer and get a current price.