While I think Vollmer has been stunningly good, BB has a well known affection for veterans and for a generally good reason, which is experience. Kaczur is nothing spectacular, but he's still a solid tackle.
I'm not sure Vollmer would instantly make the transition to RT and play as well as he has, and at the same time, I can't believe that BB will bench Light in favor of Vollmer. Light is still better than Sebastian and has more experience.
At the same time, BB is very unpredictable. I'm sure Belichick will be comparing Sebastian's performances with those of Kaczur and then see which guy gives the team the best chance to win.
Can't imagine Light starting at RT. Makes no sense when he has played his entire career at LT. The only possibility is Vollmer moving to the right side and there's no guarantee that will happen, even if I personally feel that Vollmer is a better player than Kaczur.
As I said, there would have to be some transition for Vollmer involved and some guys who are great left tackles simply can't play the right side. They aren't used to shifting their weight to that side of their body. But, it's definitely possible that Vollmer could start there, as I'm pretty sure he has worked both positions in practice and training camp and for all we know has worked there in college/Germany as well.