According to Plan for vintage Limited Edition skins | League of Legends these skins will be making a reappearance for a short time in the stores. The incentives of owning them before the reintroduction date is:
RP equal to the price they paid for the skin
Vintage treatment in the loading screen whenever they use the skin
Original Limited Edition skin owners will receive this exclusive summoner icon:
October 2013
Mundo Mundo
Pumpkinhead Fiddlesticks
Kitty Cat Katarina
Lollipoppy
Zombie Ryze
Nosferatu Vladimir
FrankenTibbers Annie
Definitely Not Blitzcrank
Bewitching Nidalee
Haunting Nocturne
December 2013
Snow Bunny Nidalee
Workshop Nunu
Happy Elf Teemo
Earnest Elf Tristana
Old Saint Zilean
Re-Gifted Amumu
Santa Gragas
Reindeer Kog’Maw
Candy Cane Miss Fortune
Ragdoll Poppy
Nutcracko
Silent Night Sona
February 2014
Vancouver Amumu
Team Spirit Anivia
Ice Toboggan Corki
Union Jack Fiddlesticks
The Mighty Jax
Festival Kassadin
Whistler Village Twitch
Curling Veigar
Please note these changes don’t have any effect on:
Limited Edition skins that were once in the store but are not part of these events (Rusty Blitzcrank, Urf Warwick, Championship Riven, Riot Singed). If these skins are ever brought back, they will be treated similarly.
Earned Limited Edition skins that were rewarded for events or achievements and never appeared in the store (PAX Twisted Fate, King Rammus, Victorious Jarvan, UFO Corki, etc.). We have no plans to make these skins available.
Other Legacy skins (Riot K9 Nasus, Zombie Brand, Nottingham Ezreal, etc.), which may still come back into the store from time to time without compensation