Samsung Galaxy S5 — Samsung S5 has 2 serial numbers - is that normal?

Hi there, I bought a "New Other" S5 with one year manufacturer warranty from ebay and just wanted advice on whether it's legit or not.

The seller has 300+ feedback of which 96% is positive and the negatives are mostly slow delivery so I felt reasonably reassured.

The IMEI check out and matched the box, housing and status info. However the serial number on the housing (under the battery) doesn't match the serial number in Settings>About Device>Status.

Using the PhoneINFO app it tells me that the phone was built in March 2014. The housing serial number manufacture date is March 2014 but the other serial number manu date is July 2014.

It also tells me that Knox Warranty is void 0x1 and the charge counter is 590.

So I think it's obvious the phone is refurbished but I'm concerned about the serial numbers not matching. Is this normal?

There is also a small gap between the bezel and the screen, maybe fingernail thickness, around 2/3 of the screen perimeter is this normal or inline with a replaced screen?

I'm going to return it but I just need to get my facts straight!

Thanks for your help,