“is it unusual to have that many Green Berets in one operation?”
Unusual, yes, but not unprecedented. It is a pretty big engagement. There are probably a good number of assorted support, admin, technical and command people; in addition to Green Beret Teams working within larger Afghan units. They don’t mass together 600 guys to fight like an Infantry Battalion.
It did surprised me when all Those Navy Seals were put on one helicopter. That was unprecedented with disastrous results. Well maybe not unprecedented but definitely unusual.