Several small variants exist on the different models.

The first and one of the most visible concerning the part in plastic on the top of the body that I would call "ladder"
They are two different types, one with a rod (last one) of reinforcement and the other without (first one):

White Eagle Freighter 2 nd release, Green Eagle transporter 2 nd release are with the two types
Green Eagle transporter 1 st release are only without the rod of reinforcement.
White Eagle Freighter 1 st release are only without the rod of reinforcement.
Blue Eagle are only with the rod of reinforcement.

As it is extremely easy to change this part of an eagle to the other without letting trace, one can find other variations but I think that it is not factory-built.