Hey Moth. Didn't realize this was you before now.
No, it's not the most accurate helmet in the world. On the plus side though, your colors are decent compared to some I've seen. As I said, not 100% accurate but at least you have the right idea going on. Light green on the top and front - darker green on the back - red on the T. I would be suprised if the colors alone would keep you out. The Testors colors are great but not easy for a guy on a budget to find or buy. There are cheaper and more comon versions of those colors in your local Wallyworld or Crappytire.
That being said, your battle damage, although unique and creative, doesn't correspond to anything we have seen on Fett. Good or bad, the 501st focuses on screen seen items. This is one of the reasons why a straight from the Quarter-Master Fett with a clean jumpsuit and ZERO battle damage would have a hard time getting in. You're both on opposite sides of the spectrum with Fett being closer to the middle.
Is the damage actually dremelled into the helmet?
I'm there for you if you need any help or advice. To be honest, I don't envy any new people trying to join the 501st right now. It should be noted that none of the Mandalorians in our Garrison (myself foremost with my first Jodo Kast suit) would be accepted if we applied today.(in our original submission photos at least)