You can take both. But take care, the UDN2981 turns-on, when the input is logic high. So, when the reset time is rather long only low currents should be allowed through the LEDs, because during the reset time the micro cannot multiplex the LEDs.

In the mentioned avr-project the current through the individual LEDs is limited by the 220 Ohm resistors to about 5mA. So, nothing bad can happen, probably. Unfortunately, this means that the display is not shining very bright. If you want a higher brightness, by reducing the current limiting resistors to 82 Ohm, for instance, you should better choose a driver, which is turned-off when applying logic high to the input, like the earlier discussed BDX54C scheme.

Good luck,

Kai