RFID reader systems, readers, components, software and methods for causing RFID tags to backscatter a combination made from at least portions of a first code and a second code stored in tag memory, without transmitting any commands in the interim. In a number of embodiments, therefore, a separate command does not have to be sent for also reading the second code, thereby saving time in inventorying the tags. Plus, the combination can enable reading tag codes during tag manufacturing that are not otherwise readily available to read in the field.