No.
You get input pullup when the bit in the DDRx register is 0 (indicating it's an input) while the same bit in PORTx is 1 (indicating high).
Set the pins to INPUT_PULLUP before hand with pinMode(), or via direct port manipulation:
DDRC&=B10101010; //Make sure that the pins aren't set output - not needed if you know they haven't been set output elsewhere in sketch
PORTC=B01010101; //PC0, PC2, PC4, PC6
or, possibly more clearly:
PORTC=(1<<PORTC0)|(1<<PORTC2)|(1<<PORTC4)|(1<<PORTC6); //set PC0, 2, 4, and 6 high - but they're not outputs, so it just turns on the pullup.
Note that on ATTiny441,841,1634 and 828, you use PUEx not PORTx to control pullups.