Replacing Internal Battery but need tips

[Spull]

 

So, I need to currently change my laptop's internal battery because there seems to be an issue with battery backup.

And since I am a student and on a budget, I am having trouble to afford for a service with the HP Service Centre, and I am currently getting the battery replaced from a local Computer/Laptop Repair store. 

So, while I am checking for the genuine-ness of the battery they are charging for - I am checking it by running command to check the Design Capacity of the Battery (because I found out that the fake internal battery seems to have the same upper as the original internal battery but when I check in the battery report, it shows a different mAh)

And also, while doing Component Test on the fake battery - via F2 while restarting laptop; it shows that the used (fake internal battery) has an age which is more, because it's a new battery it should have 0 days, no? And also should I check for the Remaining Battery Capacity to check whether the product is Genuine or not or atleast new in the terms that they are saying.

I need to know whether this is correct way to check for the genuine-ness of the internal battery as I wouldn't want to be given a used product. 

Or if there is anything else that I should check for.

The picture uploaded is the fake internal battery that the guy was telling me that's it's new.