Ghibli seat adjusters

I am currently restoring my 1970 Ghibli. Although the seat adjusters look OK there is still some minor pitting . I have a really good Chromer, but he does not know how to take apart that device due to the fact it has a square rivet which needs to be drilled out. Does anyone out there know who can take the seat adjuster apart, chrome them, and put them back together again? A contact in Italy said they can do this but I prefer not to go through the hassle of shipping. Thanks!