For production boards, is a buffer IC best to translate single unidirectional 3.3v to 5v logic without inversion?
Because your microprocessor uses 5-volt tolerant IO pins, the simplest interface is simply to configure your pin as an open-drain, then use a pull-up to +5. From the data sheet, the pins have an absolute max rating of Vdd + 4 volts, or 7.3, so pulling up to 5 volts should be no problem. And, since the pins are rated for 8 mA/ per pin, you'll get best speed with a 1K pullup resistor, while dissipating a maximum of 25 mW. 

Using a 125 is also perfectly acceptable, and if you do, just tie the OE to GND, as you suspect.