Yes, there's one "true" collection in Dressage, upper level Collection. But you have to start somewhere, in degrees of collection. For a green or non-Dressage horse, the first degree of collection is balance, with bouts of roundness and drive. For an FEI Upper Level horse, the final level of collection is elevated gaits, elevated front end/neck, a compacted body, and a lowered/driving hind end with the horse's energy "coiled" and ready to spring.
No, the green horse is not "collected" like the FEI horse is, but it is showing as much "collection" as is possible in its given state. It's the act of "collecting" the horse, that can be applied to almost any horse, at any gait, in any discipline.
Here is a good article on Collection from a classical dressage perspective. ::: Sustainable Dressage - Collection & Its Evasions - True Collection - What It Is and How to Achieve It :::