I would advise against that. I would recommend just adding the proper build.prop edits back in after installing 3.0. I think there are a good bit of differences between 2.2 and 3.0 that could result in you softbricking your device, if not careful, unless you're using safestrap. I might be wrong so I would wait and let davros, or another dev, answer your question.
Sent from my 3rd reincarnation of the ever-so-lovable Droid
thanks, i wait an answer of dev...