Battery connection method for tablet with 2 batteries

Hello all, please let me start by saying I'm not a certified tech. However I did grow up from infancy to early adult yrs (22), before I moved from home in an old school independant video/audio repair shop my dad owned and ran for 30+ yrs with the reputation of one of the best in Chicago. Plus a step dad who was a Bosch engineer automotive division for 36 yrs and then some. So I've a decent knowledge with electronics.in general and can accomplish many ordinary repair/maintenance jobs most people cannot. So when I say I have a Visual Land Prestige Elite ME-11Q please don't tell it doesn't exist yet. It may in fact be discontinued as the original batteries were produced sometimes in 2015 is all I remember about them. I have no other documentation about this tablet. What I do have is new replacement batteries that ARE of the same voltage as original oem 3.7 volt lithium ion and the mah and watt hrs are just a hair above original spec. And am goin to take my chances regardless. Now... This tablet runs with 2 of said batteries connected to a BMS. What and all I need to know is... Were they installed on the production line connected in a series circuit (my guess as it's a bigger than 10" screen with a magnetically connectable keyboard with mousepad all built in to the protective portfolio it came with, as the keyboard has zero input connectors for charging it as any BT physical keyboard will have. Or ... Were they installed connected as a parallel circuit? That's all I need and want to know. Please and thank you in advance