what is the deal with the cobra gauge cluster, up until 97 they all had a 7k tach an said unleaded fuel only, an then in the middle of 97 it looks like they changed it to an 8k tach an it to say premium unleaded fuel only, i found two 97s and hey have different clusters, and they are from reputable dealers who havent tampered with the cars in that way. did they change them in the middle of that year?