Not exactly home improvement, but my parents' business.

How hard is it to install a panic bar like this




On a door like this



I've got a drill, drill bits, screw bits. Don't have one of those circular drill cut out bits if needed. After I remove the old handle, not sure what to use to plug up the hole. I'm pretty handy with tools, but I can't remember the last time I installed a lock/door knob of any kind.

Can you just cover the holes with a couple stainless plates? Even one of the stainless rectangles used on the push side of doors may work? If it's in the back and you only care about function, that may be the easiest and cheapest solution.

Yeah, makes sense I can do that. Just seal it with some silicone or something.

I've put expanding foam in a hollow door before just to be sure. I can't tell if that one is metal or solid wood, though.

Edit to add - I see you can get covers made for the holes on Amazon pretty cheap. Search "Prime Line U 10446" and see if that would work for you. Probably easier and more secure than attaching a plate directly to the door.

If that's a metal door just pop rivet a steel plate over the hole. Bed the plate in silicone before you secure it.
Im guessing this swap is being required by code?

Yup. Gotta fix a couple things the inspector found. Old inspector apparently didn't care.

And yes, the door is metal.

They aren't too hard. To cover the holes do what they say above. You can go to Home Depot and get a Push/Pull Plate to cover the old holes. They are about 10 bucks each.