Yes, surprisingly the 500 uses M3 bolts for both the tail and main rotor blades - though the bolts are at least shouldered. I suspect that's why there is a maximum headspeed recommendation of 2650 for the 500.
Nice quality bolts, i change them every 2 years for safety reasons. This is one of the most stressed parts of any heli, so it is better to replace them periodic. For my low rpm flying, every 2 years is ok. I was surprised that i got a plastic bag with RJX label with this bolts inside, so i think the quality should be very good.