Title says it all, the selectable merc skins released in the latest patch are not present in the game, everyone is wearing the default black and white skins for friendlies and enemies respectively (although the black set has been darken on most mercs in this last patch, it is still the same boring default). Unless the intent was for us to be able to view these skins only in the customization menu for now (in which case it should have been clear in the patch notes), it looks like QA was sleeping on the job here when they let that change through. Or perhaps that limited availability thing mentioned in the patch notes was not even 24h?
Note that gun skins do appear in game, but I’ve seen a lot of texture corruption issues with those (mainly in 3rd person view but also when spectating in 1st person) and the customization menu sometimes get stuck with low-rez textures.