Sound at 55+ mph

[loren01@ix.netcom.com (Scott Bermes)]

I am looking at a really nice 89 200tqw, but it makes a noise on or 
around 55 mph and higher.  My nine year old said it sounded like an 
airplace engine wine, I thought it sounded like a pylwood saw.  The 
dealer mechanic who looked over the car heard it and said it wasn't the 
wheel bearings or anything to do with the wheels, axle.  This was your 
one hour look over and he said he would not be concerned that it was 
probably a trim piece.  The noise doesn't occur below 55'ish and it 
comes from the right middle/rear.  Any wild guess and should I be 
concerned?  

TIA,

Scott
89 200tq