I am not sure exactly the rev. now as I did not opened it yet after arriving back but as my DSP was so old I am sure that it is intermediate upgrade based on their modification list. It should be this one:
Swap out upgrade of your Pre-Rev D assembly DSP boards to a DSP board modified to Rev D. (Rev D already ships on all new K3s.) Improves low freq RX/TX audio response below 300 Hz, and adds a Low Pass Filter (LPF) that rolls off RX audio above 4 kHz. This is a fully tested and warranted upgraded board based on an exchange DSP.
Hope it helps Bob,
73 - Petr, OK1RP