Do all of the AQ6370 series have the same wavelength resolution?

​No, the resolution is going to vary based on the model. 

AQ6370D: Min. 0.02nm, Max. 2 nm

AQ6373B: Min. 0.01nm, Max. 10 nm

AQ6374: Min. 0.05nm, Max. 10 nm

AQ6375B: Min. 0.05nm, Max. 2 nm

AQ6376: Min. 0.1nm, Max. 2 nm

AQ6377: Min. 0.2nm, Max. 5 nm