Continuing the process of cloning a non-400 into a 400...

Got hockey sticks from Ames to put on my grilles. Appears they are attached with a pair of simple unthreaded studs poked thru holes which I need to drill in the grilles (on the long side of the hockey sticks). And there's a threaded hole that I can put a bolt thru on the short length. Is there any type of nut or retainer placed on the rear of these studs?

Thanks.