basically no: the hex must be stable.
Alternative: if you need separate .hex files because the sketches are NOT identically, you could give each target it's own download folder on your webserver. So two .hex files for two targets.
yes with some tweaks:
if you can put the individual "ID" in the EEPROM emulation of each target and just read this ID from the EEPROM during startup - you could use the differing ID from EEPROM in the same sketch on both targets.
Advantage: setup the ID once (write it to the eeprom emulation once) and have just one single source for both targets.