Yes, 4K 60fps could be recorded to an external DDR device once you have the RAW PORT installed. For compressed RAW (i.e REDCODE), the current limits - as expressed on Build 9 v1.5.1 - are 4K to 25fps and 2K to 75fps. Things also change pretty quick around here with new firmware builds.
p.s. Its not possible to shoot with RED PRIMES, they are not released yet.