Do you remember when or which state the signal red was in? I just looked through all the 17 signal reds in the US and found the following:
WDBEA36E8PB977696: Florida, Certificate of Destruction issued in 2002
WDBEA36E9PB978985: California, last serviced at Fletcher Jones 8/15/14, last passed smog 12/30/14 and nothing after so possible part out.
WDBEA36E3PB979484: Utah, last serviced at MB Salt Lake City in 8/2005 at 100K miles, another possible part out.
WDBEA36E7PB972330: Missouri, last serviced at Custom Complete Automotive in 4/2014 at 91K miles and registration renewed a few days later. Nothing after that.
Probably not it but WDBEA36E3PB975256 was last in Puerto Rico in 2014.
All the remaining ones, I found either a carfax service or some emission history. in the last 5 years.