I just spoke with them and got credited something like $59. For those still trying, when I got in, I immediately said that there is a promotion and others are being credited, and I was wondering if I could be extended the same courtesy. I linked the promotion and the person asked her supervisor before telling me she could do it.
So, my advice is that you immediately say that there is a promotion and others are getting credited the difference and that you would like to know (don't demand, be polite) if you could be credited as well.