So I have a 2011 iMac 27 inch and I need apple to load the OS on it (long story). My question is will they actually work on this? Will they charge a fee? Asking for a friend. 
It might help if you explain why you need "Apple" to load the OS...?
(this doesn't make sense)
"I guess OP doesn't know how to do a fresh install of Mac OS and would like someone else do that for him."
Then... it's time for him to LEARN how to do it.