This is how my Road Runner looked when I bought it. It had been sitting in a barn for 20 years after the previous owner blew up the rear end.

This is how the fender tag decodes:

Code Description
E68 400-4 Barrel High Preformance
D34 TorqueFlite Automatic Transmission
RM21
R = Plymouth Road Runner
M = Medium
21 = 2 Door Coupe

P3G
P = 400 260HP(net) 1-4BBL 8 CYL
3 = 1973
G = St. Louis, MO, USA

264037 Sequence Number '264037'
JF8 Paint Code: Unknown At This Time
D6F6 Trim Grade/Style/Color
D = Deluxe
6 = Vinyl Bucket Seats
F6 = Green

JF8 Upper Door Frame: Unknown At This Time
726 Date Built: 7 / 26 / 1973
116540 Order Number: 116540
JF8 Roof Type OR Color: Unknown At This Time
U Built to Specifications for USA Order
B41 Front Disc Brakes Some Yrs. Power
C56 Bucket Seats 1972 up
G11 Tinted Glass All
G37 Left Hand Remote, Right Hand Manual Chrome Mirrors
H51 Single Air /w Heater
J45 Hood Tie Down Pins
J52 Inside Hood Release
M21 Roof Drip Rail Moldings
M26 Wheel Lip Molding
N41 Dual Exhaust w/o Tips
N42 Chrome Duel Exhaust Tips
R11 Music Master Radio AM
V8W Transverse Stripe - White
V9W White Bumblebee Stripe
28 Unknown At This Time
END End of Codes