D usually refers to suggestive references. L means language, so there will be some degree of swearing. That being said, I don't expect these elements to be extremely heavy knowing the kind of show this is. I don't expect the suggestive references to be perverted jokes, more like mild allusions that could be potentially plot related. I don't expect a ton of cursing either, but some one's probably going to get angry. Genndy Tartokvsky doesn't seem set on making this be like one of the other crude Adult Swim shows, this is a totally different kind of show. So that's what I feel is at least more likely.
Ok, so turns out the reason for this is because the actual show being played last night was Rick and Morty. Whole thing was an April fools prank, so the rating is still the same. But we have to wait another week. Ugh.