Probably the same way there are people here who can't tell the difference between a '53 and '54 Plymouth, a '28 and '29 Model A, whatever, you name it! How can there be someone here who would criticize another's ability to differentiate VERY similar model cars???
Every time I think my memory isn't what it used to be I look at an old record chart and know I can probably remember the lyrics to most of the songs on it.