Yes. You always get nervous when new parts are involved.
I recently had a similar issue with a MAF on a Mazda. Brand new, same part number as OE, same manufacturer from a supposed reputable dealer.
I was convinced it was the MAF but not enough to splash out nearly $400 on a new one. So I sourced another genuine second hand one. Performance was increased massively.
On closer inspection things didn't quite add up. The brand new one on first look was identical and the numbers matched. But each digit was slightly chunkier. Each corner slightly radiused. The finish was slightly smoother, the detail not quite as sharp. Just like if you make a mould of something, the same but not. I couldn't prove anything but I had my suspicions.
I did have pics to put up sometime but didn't have the time but now...
. If I find them I'll post them up.