Motorsport shells didn't have sunroof and where supplied in white minuis and underseal/seam sealer so that they could have seam welding and cages fitted etc. They where not seam welded from the factory
As they are supplied in bare form it doesn't take a lot to do a full body respray in any colour.
Other tell tell signs are non rear opening rear windows and mix match of small turbo and big turbo parts.
A few pic's would tell a lot to me.