The much unloved 4400 is not super easy to get info on like some models. Its all boiler plate stuff. But I want to be sure, did the 4400 ever come with a 604e? From what I have read, no. But I am not sure if there was some custom order option.

I ask because on some boards the silk screening has jumper specs for 603e, 603ev and 604e. I attached an image and its hard to read. But to the upper right of the processor you can see what I mean. Some boards do not have these screening.