If it looks yellow-orange when you look thorugh the lens then IMHO it has turned yellow.
I noticed that on mine when I shot some color film and it looked as if I had a 81 filter on it.

While your camera is in CLA it wouldn;t hurt to leave your lens in a window sill and see if it changes

Quote Originally Posted by Uncle Bill
Dumb question of the day, the coating on the Takumar 50/1.4, is it an amber colour? I am well aware of the problem of lens yellowing due to the use of "rare earth" in the manufacture of the lens glass. I showed my lens to my camera tech when I dropped the spotmatic off for CLA and seal replacement, he is an allumini of both the Leica and Pentax service departments, he said it was the coating. For piece of mind on my part what tone of yellow should I look out for on my lens?