Dash gauge "welding"

Home is probably your best direct route for plastics rechrome.
From what I've read in the past, Those that do instrument/gauge services farm out vacuum metalizing/rechroming plastics, bezel restore in general.
There is a toy restoration company ( muellercorp or something like that ) that does it but they wont deal directly with us John Q. Public type automotive customers. I'll bet my quarter that is who Instrument Specialties uses.
Gcar is one of the very few who still do this process and will deal us individuals. EPA regulations along with Chinese reproductions forced quite a few out of the business several years ago.
The candid telephone conversations I recall about customers that expected their returned parts to look BETTER than they did when new... Charles @ CV Platers, Glen @ MrG, and more. That was just another factor in their decisions to leave the business.