The 744 fifth pod mounts was a customer option. BA's 744 had that option (all except the last few I believe... note to self to go check
).
We have used it but not often as ops don't like the penalty!
preferring to use the Russian freighter.(RB211 and similar engines will fit in a IL 76.)
The GE90 and Trent will only fit in the AN124 and even that is a tight fit
If you only need to ship a GE90 propulsor it will go into a 747 freighter.