1972
The final year of the Spectraflame era ends on a bit of a letdown. Only 7 new castings this year, 4 of them in Spectraflame paint, and then in only 7 or 8 total colors. No more collector buttons either, excepting the Canada only MAG wheel. All castings this year were manufactured in Hong Kong.
Still it's only a slight breather in the greater history of Hot Wheels.
Interiors
1972 castings included the following interior colors: ivory, dark brown, and black.
Exteriors
Hong Kong cars were produced in only 7 or 8 colors this year.
Note that there is some uncertainty surrounding lime and gold colored cars. It may be that gold cars were painted yellow, and that lime colored cars were painted light green.
Casting Names and Part Numbers
A new never before seen range of numbers for the first 3 castings, not sure why they didn't fill in some of the existing gaps. The next 3 fill in some numbers in the sparsely used 6000 range, then the final casting goes in another sparsely used range, 6100.
Seems like there was never an allocated block of numbers for Hot Wheels, maybe there was just a big book at Mattel for everything they made and they just took from the book when they needed to. Seems reasonable, but it's only speculation on my part.