Any "semi serious raiding guild" will look at how well you present yourself on Discord and how well you perform during trial. They maybe get a look at your parses and armory profile but since flying isn't mandatory in instances they probably won't give a fuck about it since getting flying right now, as a_skeleton_03 pointed, is trivial. We're talking 8.3 here, manpower is needed everywhere, it's not really a time to get ultra picky.
Unless you're in a world top 100 Mythic guild environment (where everyone knows each other) no one is gonna instantly discard your guild application before testing you in raid. Neck level farming is trivial, raid consumables (and some BiS gear) can be bought with IRL money, cloak progression is timegated and Ny'alotha doesn't require attunement. Only a fool would think one would care about a player pedigree in a season-based gameplay.