Any idea how long the shurima ward skins are for?

I'm assuming they will be in the store until the 21st of September since that is the last day of the Ascension game mode.

Anyone else? In my opinion they will just remain in shop forever, there was no information about limited time whatsoever. I'm assuming as well, that Shurima's icon is purchasable for IP in time of event, but will be purchasable later for RP.

Can somebody confirm or deny my assumptions? I already bought and spend much RP during sweet week, and have only enough for one ward, but I'm greedy for both and .