Depends on availability. For example, reds, browns, clears, whites, greens, grays and others have been scarce at different points in time. You'd have to pay premium for them at Massdrop, qtan's store and elsewhere (limited editions like filco with reds, anyone?). Besides, #vintage switches are sometimes worth more than regular/modern ones (e.g. nixdorf blacks).
Other than that, they shouldn't be priced differently... see 7bit's sale thread.