@Slay
Sorry didn't see the photo you quote because I was using Tapatalk. I was persuaded its about the 6538.
The 6542 is based on a reshaped 1655. Dial, bezel and insert are from eBay.
No minimum order, but the ad is not clear. It is not specified whether the price is for a bar or a pair. I ordered 1 and received a pair. Then a friend ordered 4 and received 2 pairs.
Those 906141 bars are available here too :
http://www.misterchrono.com/fr/outillages-pour-bracelets/2065-pompes-type-rolex-pour-cornes-percees.html#/taille-20_mm