2 is a "platform indicator", 0 is a generation number, and 3 is the code number for the memory size. 3 means 128 to 256 bytes. (0 is less than 64 bytes; 1 is 64-96 bytes; 2 is 96-128 bytes)
(http://www.nxp.com/documents/short_data_sheet/NTAG203_SDS.pd...)