that list has lots of mistakes,
well the rear spoiler did not come standard with the mach 1 package it was extra, and no cars were suppose to come with the chin spoiler except for the Boss 351. many mach 1s had the chin spoiler installed by the dealer.
the competition suspension was also not part of the mach 1 package.
also trim rings for the rims did not come after 1970 they changed the design for 71-72, 73 was again different from 71-72
the nasa hood was not optional for the mach 1 trim it came with the option, making the nasa scoops functional with ram-air was an additional cost.
the picture used for the 73 has the incorrect magnum 500 wheels, technically the 500s went out in 73 and were replaced with machined mag wheels. the standard hubcaps were also different from the 71-72.
its hard to tell at a distance a 71 from a 72 mach1, you can spot a late 72 however. the 71 rear seat belts were not retractable, later 72s had retractable rear belts. also the buckle changed from the round button to the square button. Also due to government regulation the addition of the Seat-belt warning light was added to the passenger side glove box surround.
if you spot one with a full center console and it has wood trim around the clock and chrome grill light houses then its a super early 1971 car. later the wood faux was dropped and the grill lights changed to argent.
i have a very early 1972 which used a lot of 71 parts as ford was cleaning out the parts storage when they threw mine together.
the deck lid on the 71 early 72 is slightly different also, the trunk has little feet in the steel that was later made flat and the access to the truck lock clip is different (changed due to workers cutting there hands during assembly.
some claim that the 71 and 72 faux wood trim is different also the pattern changed and the wood became a lighter color.
a 71 standard radio is different then the 72 also, it actually says mustang on it, on the radio face.
the dome light changed in 72 the lens uses a different style mount.
there are more differences, but usually at a car show when i take a fast look i can spot a 72 from a 71 before i look at the vin or part numbers.