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View attachment 1807233
Last 6 VIN digits obscured by Moderator
I don't usually dabble in your model year, but below is my best shot at it. Other members are welcome to chime in and correct and/or clarify (e.g., like what is included in the A88 decor group?).
RM21:
R: Plymouth Satellite
M: Medium, Road Runner
21: 2 Door Coupe
U3G:
U: 440-4V 280HP (net)
3: 1973
G: St. Louis, MO, USA
123456: Sequence number
E86: 440 cid 4 barrel V8
D34: Light Duty Automatic Transmission
GB5: Bright Blue Metallic Exterior Color
D6B5: Trim - Luxury, Vinyl Bucket Seats, Blue
BB5: Upper Door Frames, Blue
223: Scheduled Build Date: February 23
178836: Order number
GB5: Bright Blue Metallic
U: USA Specifications
A88: Interior Decor Group
B41: Front Disc Brakes w/Standard 10in rear drums
C16: Console w/Woodgrain Panel
C56: Bucket Seats
G11: Tinted Glass (all)
G36: Outside Dual Racing Mirrors
H51: Air Conditioning with Heater
J52: Inside Hood Release
L31: Hood/Fender Mounted Turn Signals
M21: Roof drip rail moldings
M26: Wheel Lip Moldings
M52: Sun Roof, Manual
N41: Dual Exhaust
N42: Chrome Exhaust Tips
N85: Tachometer
R11: Radio Solid State AM (2 Watts)
V8R: Tranverse Stripes, Red
V9R: Hood Stripes, Red
28: 28" radiator
END: End of Sales Codes