macOS 11.0 Big Sur compatibility with Mac Book Pro 2013 I read on macOS Big Sur Preview page that the upcoming release will support only the Late 2013 and later models of MacBook Pro.
Does it mean the Early 2013 MacBook Pro won't be able to run macOS Big Sur? What is the difference between the two?
Yes, this in fact is an existing restriction with Catalina (see screenshot). It is unsurprising that the version of Mac OSX after Catalina has the same limitation; ultimately the hardware gets left behind as it becomes incompatible with changes in the OS.
See this table from https://eshop.macsales.com/guides/Mac_OS_X_Compatibility:

EveryMac lists the specifications of the Early and Late 2013 MacBook Pros at https://everymac.com/systems/by_year/macs-released-in-2013.html