How to tell Flowmasters installed on my 2004 Mustang GT?

Okay, so I've recently upgraded from my 03 V6 to an 04 GT. It's got 8k on it, and I managed to do a trade in and only up my payments by $20. It's basically my dream car that I couldn't afford three two years ago when I settled on the 6 cylinder.

Here's the question........Under my hood, there is a FLOWMASTER sticker. The dealer didn't mention Flowmasters, but they got it at an auction from what I understand.

I don't know if it's safe to assume I've got Flowmasters based on that sticker, but how can I tell? My buddy thinks it sounds different than his 99 GT, but I'm not sure. I haven't been able to get a good look underneath yet, but it would be nice to know what I'm looking for once I do.

Any advice? tips?

Thanks..