Every fire job that I have been on with smoke near the panel, the panel got replaced at the request of the insurance company. One of the restoration companies large priorities is to free the house of smoke odor. So if there is smoke, there is smell. They can't spray the panel to seal in the smell. Outside of the smoke, you have to consider that "if there is smoke, there is fire" and everything was sprayed with, at minimum, water. Also, there are extremely corrosive chemicals that are used to put out fires.
Note the bottom of this panel after sitting for 2 months after a fire. It appeared to just have smoke damage on the cover...the wire was also terribly corroded, and the sheathing and insulation was just wrong even though it appeared fine. It was brittle and gooey, at the same time.
This one is a bit more obvious...
And notice the corrosion on the bare wire on this one...
Yes, replacement is the way to go, there may be problems if a fire restore company grabbed the job, they give a price and tell the homeowner they will restore all the fire damage, the only problem is, they usually do a quick cheap clean up job, and suck up all the insurance money, so you may have a problem getting them to spring for the new load center, they charge a lot and do as little as possible.
And in my experience with a couple of restoration companies, I have found this statement to be unequivocally false.
