I gave it my best shot. Relatively early build car. Pretty well loaded with three colors, which I alway think is neat (Red, White, Black). This car would have had a pretty high sticker price considering the AC and PW. A nice cruizer too considering AM/FM Stereo and a folding arm rest to let your GF slide in nice and close while you play those 70's power ballads on the FM band!
E65 = 400 2bbl Engine
D34 = 727 Torqueflight Transmission
R = Satellite, P = Premium Price Class, 23 = Hardtop, M = 400 Engine 2bbl, 3 = Year 1973, G (not 6) = Built in St. Louis MO
FE5 = Red Body Color
H6X9: H6= Vinyl bucket seat w/ armrest, X9 = Black in color
TX9 = Black upper door frame?
813 = Scheduled build date Aug 13
J00388 = Vehicle Order Number (Note the "J" should be a number... maybe 1 or 2).... but looks clearly to be a J. Odd.
V1W, V1 = Full vinyl roof, W = white in color
U = Made to US specs
B41 = Power front disc / rear drum brakes
C21= Center front seat with armrest
C56 = Bucket seats
G11 = Tinted glass
G37 =LH Remote / RH Manual chrome racing mirrors
H51 - Air conditioning
J25 = Three speed wipers
J52 = Inside hood release
L31 = Fender/Hood mounted turn signals
M21 = Roof drip rail moldings
M26 =Wheel lip moldings
M31 = belt/hood moldings
N95 = ?
P31 = Power windows
R35 = AM/FM Stereo radio
Y16 = Sales bank car
28 = 28 inch radiator
END = End of codes