not eaxctly sir, anywhere locos are made with two different gear ratios to suit requirement of the load it is pulling.. WAG/WDG's have gearing set in such a way to provide more torque while starting while WAP/WDP's are set in such a way that it gives faster acceleration..while the have the same power rating.
Example is WDP-4B and WDG-4, WAP-7 and WAG-9 etc..
WAG-9's are very much used and so are WAP-7's , they are built seperately to suit different loads..