I think Ray will assume body language of some formality with his hands by his sides and congratulate his teammates.
I think whatever 20 does will be banal and appropriate for the occasional. What would a "consummate" professional do. He will be polite and show decorum.
For me the real question is what will Rondo, KG, and Pierce do? Dap or no dap? I really dont know but I suspect they will be restrained and minimalistic but will acknowledge Ray in a brief way to meet the bare minimum of social norms.
Play smart, channel the feelings towards agressive play. Lets do this.