got mine on ebay, better quality then what came with my rep, only downside is that they need modifying (rear part sanded ever so slightly) to fit. So I have yet to even fit the black I obtained. Silix sent me one, but the pearl was off centre and it was pretty shitty
There was a tutorial on repgeek i recall as to how to modify the one from ebay
Otherwise any of the sellers can obtain, but tend not to show an interest in getting such a small part unless you also order a watch at the same time.