Using Resistors with LEDs

Is it wrong?

Let me check:

Let Vcc = 5V
Let LED V_f=2.3V @ 20 mA
5V - 2.3V = 2.7V
R_CL = 2.7 V/0.020 V = 135 ohms

1 k != 135 ohms

Note: The OP's using RGB leds so his results (forward voltages, all different for R, G & B) may vary.

Yes, it's wrong.