Well it kinda is. I assume better tickets are available for all pre sales then the general public sale.
This is, nor has it ever been true for any show, concert, band, or anything that sells tickets and uses presales. Unless they are paid for fan club presales, such as 10C for Pearl Jam or Nightrain for GN'R.
Presales are just mini onsale times with varying tickets throughout the venue (bits here and there - and yes, there are sometimes really good seats, but there are also really bad seats thrown in - it's a mixed bag).
They're a marketing ploy (unless they are the fan club paid for membership presales) to get people to think that they're getting something better so people sign up with their site or product. Only thing that's "better" about a presale is if you get lucky enough to score tickets (especially good ones) then you don't have to worry about getting them when the public onsale happens.
Back in the old days of physically lining up overnight for good tickets, what a presale consisted of was if you knew someone who worked for Ticketmaster and happened to also be working the morning of the onsale time, they would bootup their system wait for the system to start selling tickets and buy you some really good tickets before they opened the doors. If you ever sat outside (sometimes in the cold) looking through the glass at the TM employees as they typed away on their computers (this during the times of no email) for a few minutes and you wondered why the doors weren't opened when it was passed the onsale time, now you know. The start of the "presale". LOL.
AC