No, to the best of our knowledge, 2C-B does not appear to be neurotoxic, but I doubt there have been any real in-depth studies and scientific analysis of this. Looking at the lack of reported adverse effects of 2C-B and others related to it by users, as well the fact that related serotonergic psychedelics (such as LSD), having been studied, do not demonstrate any sign of neurotoxicity, I think we extrapolate from that 2C-B is unlikely to be neurotoxic (at reasonable doses I guess...)
It could be too much, but if you have had substantial experience with high doses before, you may be fine. I'd be hesitant, particularly as you sound unsure of the quanitity of 2C-B per pill- it could be a bit of a shock if one of the tablets is substantially stronger then others. Either way, follow your gut and be safe