Is it safe to drive directly from a pin?
Well the spec sheet says: 4.5 Volt 0.021 Amp. So that would on the surface say it would work great with an Arduino output pin. However (seems there is almost always a however) incandescent lamps have a property that initially there cold resistance will be lower then it's running resistance. So what is it's inrush current, and would it exceed the Arduinos absolute 40ma limit. I don't know, do you? I guess you could measure it's cold resistance to see how bad a situation it might be, but that doesn't tell you how fast it's resistance increases from inital turn on.
I would rather ask, why use an incandescent lamp at $2.73 a pop, marked down from $3.25? High brightness white leds are cheaper (.32 each in bulk, link below) then that and have no current inrush problem, and don't burnout like incandescent lamps.
Lefty