Wherever you go, take pictures of your "group" of parts before you send it out! Make an 8x10 print and include it sealed in a
page-protector along with your shipment. Put your name, phone number (at a minimum) printed IN the image; email and return ship to address won't hurt either. Simple part description also a benefit.
If you've ever been in a plating plant__literally H-E-L-L on earth__it is a miracle (and a
compliment to all the good shops) that ANY part EVER gets returned to its owner; there are just so many stations that a part can be mislaid, let alone fall off a rack and settle into the abyss at the bottom of the tanks (several, when you include cleaning/acid or caustic, copper, nickel, chrome and rinses). Equally amazing that anybody walks out alive; I rank plating shops as one of the most dangerous places I've ever worked! But for all our's sake, I hope they're not banned any time soon...
Disclaimer, I've never fought in any of our country's battles, so plating shops stop short of being shot at, as far as occupational hazards go.
I had mine (100/6) done by Al's Polishing Shop in Toledo, Ohio, when I lived there. When I took the parts in, I was warned that the process may not "throw" enough material under the drip-lip at the leading edge of the top header, but it was certainly done well enough for me (and I'm hard to please).
(address & cell # blanked out for www posting only)
These three (3) images represent ALL the post-manufacture chrome plating work that I have ever had done, and in my case, everything turned out great; no parts were lost or damaged, and all plated to a high__in my opinion__level of quality and originality. Additionally, the chrome plating has held up fantastically (>14 yrs later) and still looks as good as when I first got them back.
I hope that you have at least as good of luck!
One (1) last note, and that would be to thoroughly research the method to replace the rivets that secure your vent window hinges; I'd read up on that task years ago, making me thankful to have sidescreens instead.