are these sites using zen cart?

i am looking to design a similar site and was wondering if these two sites are using zen cart, oscommerce or what?
or could you recommend what i should use?
http://www.intrepidsuntrek.com/
http://www.trekamerica.com/
i like the way the tabs having details, itinerary, dates and prices when you click on each tour also you can see how many seats are available.

They are not using anything related to Zen Cart or osCommerce. Both of them, especially suntrek, are heavily dependent on customized javascript functions for operation, and suntrek may even be a one-off.
You could do a site with functions like those in Zen Cart if you have the scripting knowledge required. There may be some addons available to help you, like Tabbed Products Pro in Free Addons.