I doubt it will work, but it would be worth a shot sending a support ticket to see if you can get them back, if not you have a neat border once you get the skin.
In the future Id suggest investing some time into researching into things like that before you buy them. As olean said;
{quoted}
You don't see things like Star Guardian borders on Dark Star skins, or PROJECT Yasuo's border on High Noon Yasuo, so just from that alone you should pick up on the fact that borders are relevant to the skins they're made for.
mistakes happen, thats fine. Just make sure you know for sure what you are getting into before you get things like this.
Im aiming for that same border but I dont think Ill buy the skin for a little while as I dont play enough to give me an excuse to at the time. Since I dont play much Ill take as many tokens as I can get before the event ends and spend it accordingly.
I would go for the Darius skin/border, but I already have dunkmaster so I dont need to buy another skin for him