555 timer circuit power consumption
The 555 «traditionally» consumes a milliamp-wise current, like 5-10mA. In your modified circuit, what the LED will consume is negligible compared to the 555 itself. The LMC555 is its CMOS version, which brings the supply current down to the micro-amp domain, i.e. like 250µA max @ 5V. So the CMOS version will greatly increase your battery life.