Here is the Rennlist 928 vin decoder results...says it's a 5 speed GT, Or if you go one step further and select style, you can choose 928 S4 auto. I suspect, the dealer didn't.
http://rennlist.com/forums/vindecoder.php?vin=wp0aa2925ms810123#vinDecoderFar ea
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Note: This product is intended to provide a general description of the information generated by the entered vehicle's Vehicle Identification Number (VIN) and some pieces of data may be general to that specific model and not entirely accurate for the vehicle specified.
1991 Porsche 928 2dr Coupe GT 5-Spd
VIN: WP0AA2925MS810123
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Summary Style & Trim Equipment Colors Tech Specs
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General Information
MFR model code
928940
Body type:
Pass Doors:
0
Alternative name:
Alternative body:
Drivetrain:
Original Pricing
MSRP
$78,800.00
Invoice
$65,395.00
Destination Charge
$700.00
Engine & Powertrain
Type
8 Cylinder Engine
Displacement L/CI
5.0/302
Fuel Type