not sure but my guess would be no as the only 2 ways i know to get them onto the Xbox are via FTP or by an auto installer disc. and for both of those you have to have a modded system.
Some people would argue that you can because they don't consider soft-modding to be real modding. And it's been argued both ways. Bottom line, one way or another, there is no disc you can stick into an xbox right out of it's new packaging, that will play old emulators on it. You'll need to change the basic functionality of the unit. Softmodding has become very basic and simple; so it really isn't difficult. But yes; you will have to change your system, one way or another. Although you don't need to *open* the case.