brake master cylinder mounting studs

I am getting ready to install new master cylinder into my 1972 Duster and before removing the old master cylinder I noticed that one of the nuts that's hold the master cylinder to the fire wall is missing and also looks to be pretty short to even hold on to a nut in the first place, my question is if the stud needs to be replaced how hard is it to remove the stud protruding through the firewall. It seems like there are the same as the studs that hold your wheels lug nuts. I also need to know if I need to order new studs or can I go to any hardware and just order a bolt that's long enough to fit through firewall. I seen that ebay has a set for $30.00 seems kinda high just for needing one stud.


New Brake Master Cylinder Mounting Studs Hardware Dodge Plymouth Chrysler Mopar | eBay

What are your thoughts...