Thinkpad T480 with dummy internal battery

[A Monell]

I just received a refurbished T480 from Amazon. I opened it up to check the fan and whether it had a 2.5" drive or a M.2 one in an adapter. I found it has a dummy internal battery and I searched and found out some were sold this way. If I purchase an internal battery will it work OK or were the connectors for a battery disabled or a different bios used?
Has anyone put an internal battery in one of these?

[RealBlackStuff]

The T480 can run with only intern, only extern, or with both batteries.
No change of settings necessary.
Make sure to buy a genuine Lenovo internal battery (all 24Wh):
01AV419 Panasonic
01AV421 SMP
01AV489 LGC (in my T480, very good)

[A Monell]

Thank you RealBlackStuff, my concern was that as this model was sold with no internal battery and actually had a dummy, they may have had a different bios (why have a bios that suggests to disable the internal battery if there is none?) Or were selling off boards with problematic internal connectors.
I am hoping someone with experience or knowledge of with that particular model or option might clarify things before I go hunting for an OEM battery or ask what more available third party ones people have had good luck with (any hints on that her would be nice!). Thanks for the battery numbers.
Luckily it does have an extended removable one so is quite usable.