Were Carboniferous plants more efficient sequestering $\ce{CO2}$ than present plants? The Carboniferous was a period where CO2 levels fell drastically.

Source: Geologic history of seawater: A MAGic approach to carbon chemistry and ocean ventilation
I think the main reasons are tectonic settings and the formation of coal deposits with the arrival of lignite-rich plants that bacteria didn't know yet how to decompose.
My question here is:
Forgetting Carboniferous plants were efficient sequestrating CO2 forming coal deposits after dying, were living Carboniferous plants more efficient sequestering CO2 than present plants?
Meaning, would a Carboniferous forest be more efficient than present forests to sequestrate CO2 nowadays?
Probably not.
The biological pathways to make lignin is the same in all plants so there is no reasons to believe they would be better. If anything modern trees as a whole may be better since they survive in  larger range of environments and very dense wooded trees exist. In addition without defenses against modern wood decomposers Carboniferous plants may have a hard time surviving in the modern world.