Respawn are free to sell recolors of battle pass skins as they see fit. They've already done so with several legend skins. Just several weeks ago they sold a recolor of a well-regarded lifeline skin from an early battle pass. I don't expect them to do so with lvl 100 weapon skins, but who knows? In S11 the ad copy for the battle pass was changed, and they can freely sell anything again that they want to from S11 onwards.
Edit for OP: I don't think you can purchase it right now, but the Champion Edition comes with a Flatline skin (Slayer's Lancer) that has iron sights just about as good as those on Heat Sink. You could probably purchase a digital code for the edition second hand, or wait until they figure out what they are going to do with the stuff from this edition going forward.
