Depends on what vintage. If you are comparing the latest highest efficency vfd rated motor to a 50 year old unit the answer is that the starting current on new motor when started across the line might be double the old one. Does not have much to do with being vfd rated though.Will a VFD rated motors run or react differently with a across the line full voltage motor starter
you can add an external fan to any motor. but usually it is not needed unless the motors will run at full load at very low speeds, or even at zero speed. not real common but not unheard of either. these days most decent motors are going to be suitable for use with inverters anyway.I’ve heard the air flow / cooling / fan is also something that can be different with inverter rated/duty motors since at lower speeds it won’t get as much air flow from the fan.