I have a 62 and have worked on others. I suspect that the main differences between these is the degree of personal attention the embouchure hole, tone holes, and possibly bore get, e.g. undercutting of tone holes, which can adjust intonation, response, and evenness of tone. Not many people can do this work, so demand has to be reduced somehow. Price is the easiest way.
But 62 is a fine piccolo. It was top of the range for Yamaha for years. The fact that it is still available in spite of the higher models is testament to its worth.
Note that it is important that a piccolo has zero leaks. If it has no leaks, and you put a cork in the end, then with care and good embouchure you should be able to play a very quiet note approximately an octave below the normal low D.
I am not certain whether the heads are interchangeable with the metal head model, but it is likely.