Spoiler: they don't look exactly the same
I've heard people bounce between saying Watch Dogs looks pretty alright and Watch Dogs looks like someone defecated into their eyeballs. This is because we are on the internet and people on the internet get very upset about how videogames do or do not look.
You can look for yourself. The E3 2012 footage versus the retail copy on ultra settings, generally in the same area though during a different time of day.
If this bothers you -- genuinely rocks you down to your core and makes you want to lash out on the internet -- please find creative and constructive outlets for your strong feelings. If your response is milder; 'oh, bummer it didn't end up looking as good as it could have,' for example, you're fine, but I hope you also have the same outlets. We all need outlets. Where else would we stick our electronics in?