Lab ID?

[The Legendary Joe]

Both entrances work, I honestly prefer the front entrance rather than the sewers for first time visitors due to the fact that you enter RIGHT next to the warper NPC.

Front entrance requires geek glasses and grandpa beard to be worn until you get inside the actual dungeon, or the NPC's won't let you in. The NPC to get into the labs is one of those non-relevant maps Alchemists have to pass through to get homunculus. This way doesn't require you to do the quest to get in as long as you have the keycard equipped. A nice little skip for account full of characters.

The sewers is just the way in you learn when you talk to the guy again after going through the cube room, but I don't think you even need the Keycard for that. However I think this cannot be accessed without doing the quest.