Can we be 100% sure just on this alone?

Just because they didn't offer the control as an option doesn't necessarily mean that the radio can't support it. I base this on two ideas:

1.) In other models the radio was installed in both trim levels -- one that offered the steering wheel controls and others that didn't. i.e. in 2001 you could get an EX without leather 4 cyl that has my radio but not the steering wheel controls. In older 98+ Accords I think they used the same radio in many of the trim levels.

2.) Talked to a knowledgeable guy at www.logjamelectronics.com He said that the steering wheel control is very simple, usually one wire. To me it would seem trivial for the feature to be enabled on the radio itself -- even if the actual trim of the car didn't include the controller