Hello and thanks for using Just Answer, those numbers reveal nothing relevant to Fiat from what I can find. Maybe Valeo could tell you more, those numbers may be just for Valeo to tell what batch number the plastic came from. Valeo makes plastic parts for just about every brand of car. The peice looks like at came from where an inner fender skirt connects to a bumber cover. The part numbers are probably still hanging off the car on whats left of the plastics. Your best hope would be it was someone nearby and perhaps the cops can see how many Fiats are owned nearby and call and question all of them. UNfortunately you'll probably never know. Good luck, hope this helps, if it does PLEASE hit ACCEPT.