So i eventually grabbed all the bits i needed to upgrade my chatterbox from GS 490 to GS 500. My damage on the 490 was 18.7 so after spending a few hours getting the mats to upgrade I crafted a GS 500 model with 16.2 base damage.
I'm currently one up on you. I upgraded mine from 490 to 500 and it dropped 600 points of damage. I re-rolled it at 500 and the damage dropped to being literally 100 higher than the base amount. I broke it for fragments.