Well it depends what part of the site you're looking at. For example...
If you're viewing the pages by category - for example
Movie Monsters - the patterns are generally sorted by popularity, with the more popular ones at the top. Although, I have control over the order, and sometimes I'll slide things around to group certain related characters together. Also, the newest patterns for the current year are usually added to the very top, regardless of popularity.
However... if you want to know the order of the pattern releases, you can see that order when viewing pages by year. For example, take a look at the
patterns for 2012. The oldest for that year are at the bottom ("Cemetery Zombie" was the first of 2012) and the most recent for that year is at the top ("Haunted Manor" was the last pattern released right before Halloween).
If I understand you correctly, viewing each year's page should give you the order you're aiming for.
Also, notice that if you go to a pattern's individual page you will see a number in the address URL. For example, Sparky's address is:
http://www.zombiepumpkins.com/sparky-pu ... ttern/336/
So you know he's pattern #336. That's another method you can use to order your patterns by their age.