Here is a thread that discusses Red/Clear aftermarket tail lamps in depth. Found one 1990-1991 in the thumbs of NYPD blue and was shocked that we have one listed as those tail lamps are extremely rare and not many exist today.

Here is the thread if anyone wants to peruse it: http://www.cb7tuner.com/vbb/showthread.php?t=16550 - The pictures still work on the thread so you can compare the 1990-1991 red/clear to the 1992-1993 red clear