I don't necessarily see how the information is conflicting. you can use bass blockers even if the amp has a crossover. If the crossover on the amp is set to cut off at a lower frequency than you like, then bass blockers may very well improve sound quality. Perhaps that is what he was referring to.
Besides that, I don't know if it does have a crossover or not, but they are $10. Buy a couple and try it both ways. It's not that big of an expense. If I had a way to test this for you I would as I have a stock monsoon setup, but I don't even know how to test for that.