I was upgraded to a bitcointalk member on the 24th of May, and I implemented my Waves sig that same day. I sent PM to devs on the 1st of June for sig bounty. I checked the list and my name is not on there.
You needed to fill in a form to get the signature bounty. After filling in the form you were meant to check if you got added to the spreadsheet and if not to contact the devs. I'm assuming you didn't do this? Anyway it's too late now since you are not on the spreadsheet you aren't eligible.