It seems a bit steep to me, but, I'm not that well versed in winches and such. I used a generic mounting plate from Superwinch, came with the winch I bought. If purchased seperatly it would be around $100 give or take.
With a little grinding and/or drilling, you can get any winch plate to bolt to your Jeep.
But then you have to trust that it will stay there when you use the winch.