What would you do? NOS flow master muffler

[CooLManZilla]

Weird situation here. I was sent a birthday gift of two flowmaster mufflers.
I know the mufflers were purchased as new.
when the package showed up today I immediately saw something was strange.
I got one factory sealed box and one taped up old box. When I say old I’m taking about The box had a picture of a SN95 Mustang on it and the box didn’t say .COM on it anywhere! The muffler in the old box appears to have never been installed. It’s a 409 stainless grey case muffler with the old part number.
what would you do? Would you install a mismatched set like this in your car or make the seller take it back and exchange it?

[FordNut]

I would want a matched set, whether both are the old style or both are the new style.

[CooLManZilla]

That’s along my line of thinking. I wish they actually sent me two of the old ones.
i wonder how the sound would be affected with one stainless and one aluminized steel.
way different sound on the tap test.