Yes, we always rhodium plate our white gold jewelry, such as rings, earrings and pendants.
The reason we do this is because white gold is really a combination of a white metal (normally nickel) mixed in with yellow gold. The white metal helps to whiten out the yellow gold, but compared to a natively white metal such as platinum, it is obvious that it still has a yellow tint.
Thus, we always plate the white gold with rhodium, a sister metal to platinum, to give it the true white finish similar to platinum jewelry.
Over time, the rhodium plating will wear off, and you will need to have it re-plated (usually every two years). However, white gold with rhodium produces a much more lustrous, more hypo-allergenic, and white finish than white gold that is not plated.