Based on the GM RPO Code listed in this thread, here is my 81 code breakdown (minus 12 mystery codes???)
A01 : WINDOW, TINTED, ALL SHADED, W/S
A31 : WINDOW, POWER OPERATED, ALL DOORS
A90 : LOCK CONTROL, RR COMPT LID, REM CONT ELEC RELEASE
AG1 : ADJUSTER, FRT ST, POWER, 6 WAY DRIVER, SPLIT BENCH
AM6 : SEAT, FRT SPLIT, 3 PASS, CTR ARM REST
AT6 : ADJUSTER PASS ST BK, MANUAL, RECL
AU3 : LOCK CONTROL, SIDE DR, ELEC
B32 : COVERING, FRT FLOOR MATS AUX
B33 : COVERING, REAR FLOOR MATS AUX
B48 : TRIM EQUIPMENT, LUGGAGE COMPARTMENT
B51 : MOLDING, ROCKER, EXTRA WIDE
B85 : ORNAMENTATION, EXTR MLDG BELT REVEAL
B93 : ORNAMENTATION, EXTR MLDG, DR EDGE GUARD
B94 : FENDER EMBLEM, Z28
BC1 : ORNAMENTATION, INTR, I/P
BF2 : COVERING, FLOOR CARPET, DELUXE
BS1 : INSULATION, ACOUSTICAL PKG
BY1 : ORNAMENTATION, EXTR EMBLEM, BODY, VAR 3
C04 : ROOF, COVERING VINYL PADDED, RR
C49 : DEFOGGER, RR WINDOW, ELECTRIC
C60 : HVAC SYSTEM, AIR CONDITIONER FRT MAN CONTROLS
C90 : LAMP, INTR, FRT AND RR DRS, COURTESY
C93 : LAMP, OPERA
C95 : LAMP, INTR, ROOF, COURTESY AND DUAL READING
CD4 : WIPER SYSTEM WINDSHIELD, PULSE
D64 : MIRROR I/S, RH, SUNSHADE, ILLUM
D68 : MIRROR O/S, LH & RH, REM CONT, PAINTED
E5Z : SPEEDOMETER ADAPTER (DELETE)
FE3 : SUSPENSION SYSTEM, SPORT
G80 : AXLE POSITRACTION, LIMITED SLIP
G87 : RING GEAR, 8.50 INCH
GU6 : AXLE REAR, 3.42 RATIO
J41 : BRAKE SYSTEM, PWR, FRT DISC, RR DRUM, CAST IRON
J50 : BRAKE SYSTEM, POWER
K09 : GENERATOR, 120 AUP
K34 : CRUISE CONTROL, AUT0MATIC, ELECTRONIC
LC2 : ENGINE, GAS, 6 CYL, 3.8L, 4FI, V6, TURBO, HO
MW9 : TRANSMISSION, AUTO 4 SPD, THM 200, CONV CLUTCH
MX0 : MERCHANDISED, TRANS, AUTO PROVISIONS, O/D
N33 : STEERING COLUMN, TILT TYPE
N89 : WHEEL, TURBO ALUMINUM
NA5 : EMISSION SYSTEM, FEDERAL, TIER O
NP5 : LEATHER WRAPPED, STEERING WHEEL AND SHIFT KNOB
NQ5 : CAP, STRG WHL HORN, DELUXE
T47 : HOOD, TURBO
T63 : ALARM, HEADLAMPS ON WARNING SYSTEM
T82 : HEADLAMPS, AUTO ON-OFF CONT
T87 : LAMP, CORNERING
U52 : CLUSTER INST, ELECTRONIC
U75 : ANTENNA, POWER, RADIO
UA1 : BATTERY, HEAVY DUTY
UQ1 : RADIO PROVISIONS, FOR STEREO
UW4 : SPEAKER SYSTEM, 6, DUAL FRT DASH MTD F/D, DUAL
UX1 : RADIO, AM/FM STEREO, CASSETTE, EQUALIZER
V73 : VEHICLE STATEMENT, USA/CANADA
VD6 : BUMPER PROVISIONS, FRT, ALUMINUM
VD7 : BUMPER PROVISIONS, RR, ALUMINUM
VK3 : LICENSE PLATE, FRT MOUNTING PKG
WG1 : SALES, PROCESSING FOR DR POWER SEAT
Y56 : MERCHANDISED PKG, GRAN TOURING
YR1 : SEAT,FRT CUSTOM
YS1 : SEAT,RR CUST
YT1 : BUILD UP DR & QTR
YT9 : OPTION PACKAGE, FISHER FURNISHED PARTS
15U : PRIMARY COLOR, EXTERIOR ASTRAL SILVER (91)
829 : SEAT BELT COLOR, MED DK GRAY (91)
82D : TRIM COMBINATION, CLOTH, MED DK GRAY ( D) (91 )
82I : INTERIOR TRIM, MED DK GRAY (91)
84Q : MOLDING COLOR, HAWAIIAN ORCHID (92)
RPO CODES WITH NO EXPLAINATION:
D7I, FFL, GMD, P0N, QYZ, TT5, W05, 6YX, 7YW, 8PZ, 84T, 95J