I think it's about time for this prop to hit. This is mostly a gut play. When I try to figure out the odds of overtime using SDQL and look at playoff games where the home team is favored between 1 and 5, I am coming up with closer to 12/1.
I found a couple shops offering 15/1 and got another $60 down there also. I think this is a good bet at 14/1 if you can find it.