NA Rebuild - Radiator Cap

Miata has started now, but at idle and some low revving, the temperature going little higher than normal. I also have a small leakage from the radiator cap... so now i have to replace: radiator cap, thermostat, coolant, and i must clean the radiator.

But this is the NA radiator cap: 

Will i find dead animals in the bottom of radiator? O_O I'm worried about that!