That type of extra small and precise welding is what MicroPrecision Welding does.
Under a 'scope if necessary, Laser welding, welding using filler wire down to something like .005" dia. Crazy stuff for somebody like me to see that never got much farther than torch and a bit of TIG on an antiquated machine.
A fellow smith had a shotgun action w/some pitting on the top tang right up to and around the gold inlayed SAFE marking. His intention was to have the pitting welded , then faced off and have me recut the engraving. He asked and I figured it would be wise to pull the gold inlay out before the welding of course since it would be right up against one another.
No problem they said,,and they did the welding with the gold in place never disturbing it. Barely needing any work to face off the extra fine filler weld then recutting the small amt of scroll to complete the job.