There is a Huge difference between these two symbols. Mayan calendar counts time by days from one day, month, year to billion and billions of years. They have well over 20 calendars, including the Long Count Calendar which ends the 13th baktun period that started August 11, 3113 BC on December 21, 2012. Again, the current 13 baktun cycle ends on December 21, 2012. However, the new found 17 baktun cycle extends the Maya time line for an additional 1,124 years to the year 3,136 AD. You should note that the dates on certain monuments extend farther into the future, such as the inscription at the site of Pakal’s tomb at Palenque. Pakal’s tomb is inscribed with his birth date plus 20 baktuns to the date of October 13, 4772 AD, which indicates that the Maya had all intention of extending time far into the future. The Mayans were the most advanced in mathematics and astronomy of all the MesoAmerican cultures. All the other cultures borrowed from them. Aztec stone is not a calendar, it is a symbol describing the periods of the 7 suns. There is no time or date associated with the Aztec stone, it is all symbolic. With the Mayans, however, everything is calculated down to days etc., and theirs is the most complex, intricate, meaningful, accurate, interconnected, cosmic, solar, Venus, astrological, outward looking, prophetic calendar ever designed by man.

Source: Native American Indian Culture