Would introducing a koi at this time of year be fatal?

[Crystal]

I have an established pond and they are currently in a non-feeding state. I live in the desert so feeding is just around the corner. My dilemna - I came across two butterfuly koi I really want to buy at a petstore and know they will not be there much longer. Would introducing fish at this time of year be fatal to them. I know to let the bag float to acclimate them to the cold water, but would they be ok going into a non-feeding state when they have been in a petstore environment all winter long? Butterfly koi are hard to find in my city and these were just left over from last year. They are a great deal since they are only selling them at a regular koi price and have had the winter growth from being housed indoors. They are only selling for $5.00 each so it is not a money issue just don't want to kill them.