Jack,
The 8051 ports default to a high state on reset. In general, it is good practice to activate external devices, such as the clk input of a flip-flop, with the port line being pulled low. This could call for a transistor or an inverter depending on the logic you are trying to activate. (Sorry if I am stating the obvious). If you clr the ports in you startup routine then you will see a glitch on the port pins.
Allen