i see everyone else has beat me to it, but Steve, a bad credit is a bad credit...if you pubbed in The No-name Journal and the agent has to google it to find it (they won't) it says "this guy is new". If you trot that out like it was an invite from the Queen of England, then they have to decide if it says "this guy is new" or even worse, "this guy is a naive dick and nightmate to work with". Neither are good.
This is almost the exact same thing as anywhere else--in the biological sciences, it isn't like you shoot for "The Teeny Journal of Armenian Biosciences" in the hope eventually the folks at Nature will take you; your prior pub will actually work against you. Because it says the only place you can go is as a small fish in smaller ponds. It begins to create low, low expectations. So, you shoot for the top of what is reasonable, and work your way down....and when you get to a certain level, you stop subbing instead of sinking low enough it actively hurts you.