Looking into TechFiles and assuming Resistance will not be appropriate way.
But as Convention, more the Width less the resistance.
You can check the QRC/StarRC file which will have these information about resistance.
In your case, foundry might be old hence M1 is same as M5.
Usually, M1 will have different width and resistance compared to M2.
M2-M5 might (most cases) will have same resistance if they are of same type of Metal.
Check the Metal Stack information.
M1-M5 : Might be of Same type of Metal (Mx/My/Mz)
This info will be in Metallization table of the respective DRM