Registration ended on Sunday, May 11th, so yes, it is too late to register.
Tommy O- This is copied from directly above where I'm typing this comment:
"About this tournament
The link above contains all of the information necessary to sign up and participate in the Vibram Birdie Bash"
Players are registered, but I have not posted their names to DGS, sign up was cash pre-reg only through the top score website.