Passanger side door jam will have a white sticker on it that says it's modified by Roush, and will have a four digit build number.
In 2001, there were several versions that had a V6 option. The two most common where Sport and Stage 1. The Sport had a Roush body kit and side exit exhaust, floor mats and trunk mounted tool like with all the Roush logos etc... The Stage 1 added the Roush four post wing, 17" Roush wheels and Roush V6 suspension package. The S1 had optional white face gauge cluster, CF dash trim, and Roush sport leather seats as well, but not all got them.
The other option is that it is a "Wing and Wheel" package -which means it has the Roush 4 post wing and 17" wheels on it.
Post a picture, it will help confirm it .
Should look something like my old 2000 V6. I upgraded to the 18" wheels and have a Y2K R cowl hood...but other than that, it should be close.