They will fit but they are not the same. The 62 has a different configuration to the rear packs and the little keepers are plastic lined to reduce friction.
It is said that 62 packs are less prone to sagging. Plus, the individual leaves on 62 packs are just a hair thicker than the individual 60 leaves. The differences are subtle, and from 10 feet away, invisable.
I've just spent many quality hours this weekend making up beefy spring packs from FJ62 and FJ60 springs for my spring over. I also used slightly modded FJ62 springs on the back of my FJ40 spring over.
Just curious what you're wanting to accomplish?
I'm wanting to put 62 springs on my 60. If you have some good, arched 62 springs you can have my flat, saggy, non-sprung 60 springs.
Here is what I was hoping to do. There are two of us in the local LSLC club that have daily driver FJ62. We are thinking about finding a core set so we could have our springs re-arched.
It might be a mute point - I have not even looked into a re arching shop here in town.