Toonami is seriously going to air Black Lagoon? Isn't Toonami for kids and teens (haven't watched Toonami since Naruto first aired so it's been quite a few years)? Black Lagoon is rated for Mature Audiences. so if they really are then the series is going to pretty much be completely edited and censored, it won't be worth watching then.
I could see Black Lagoon being aired on Adult Swim rather than Toonami unless Toonami isn't airing it until like midnight. which I think they have done with a couple series a long time ago.