you know one give away that your car was an original slant six or 318 car..........
the deck lid emblem.
slant six and 318 cars came with cursive "Dodge" like you have there.
A true swinger 340 will say "DART Swinger" on the deck lid.
not many people notice it but it was a difference in 70 only.
71 had the block letter and the emblem was the same part number as the emblem on the decklid of 69 swinger and swinger 340 when there was no bright trim on the deck lid but just the plain emblem.
72 yet again changed but 1970 was the only year the base swinger and swinger 340 had different emblems on the lid.