As an update to a few points having spoken to my father today:

1) The 426 fender emblems were not removed upon initial purchase: they were on the fenders until at least early 1972 when my father repurchased the car. Sorry for the incorrect info.

2) The 426 air cleaner decal: the car never had one. Another Hemi car, ordered by my father's friend through the same dealer (Franklin Motors) and delivered in May 1966 did not have the decal either.

Ed
EastCoast Land Yacht Assoc.
1967 Newport Conv: 440/4 speed
1969 GTX: 440/4 speed, TX9/TX9, A34, N96
1970 Super Bee: 383/4 speed, B5/B7
1970 Coronet RT: 440/4 speed, A34, N96
1970 Coronet RT: 440/auto, A36, N96
1970 Road Runner convertible: 383/4 speed TX9/D6XW
1970 GTX: 440+6/727, A32, N96
2001 Dodge 2500 HO CTD, 6 speed, 4x4 quad cab long bed
"The early bird may get the worm, but the 2nd mouse gets the cheese".