Ask for recommendations for platers from other restorers. Some platers are excellent, some are butchers.
I once sent two really good Triumph rims to a plater for re-chroming. There was no rust, just worn-down chrome that had dulled.
When I got the rims back, some goon at the platers had belt-sanded them to a point where the spoke holes were mad oval, and spoke nipples would have pulled through them. The rims had been destroyed, turned into useless - but now EXPENSIVE - junk.
As to spokes: Tinker is not correct when he says "spokes were NEVER chromed."
1956 and '57 Triumph T100, T110 and some TR6 models, as did the first year of the "Twenty-one) 350cc unit construction bikes, DID have chromed spokes.
You will never find reference to this in "the books" or service bulletins, but I have several original, unrestored front and rear wheels as evidence, such as '56 wheels with original 9-gauge spokes, and '57 wheels with 8/10 gauge spokes.
Plus, a friend had, in 1970, his brother's original '57 T110, bought new, never restored, which came new with chrome spokes.