Yes, but things can't be exactly as you want them.
With the given values for orbital radius and orbital period (assuming 60 days for "a few months"), you can use Kepler's Third Law to derive that the parent body's mass must be about 2.2*10^25 kg, which is about a quarter of the mass of Uranus. This number would be smaller if you want a larger orbital period. Gas giants of that size should be possible, but it is unknown if any exist, and it won't be close to Saturn, which is about 25 times larger than this gas giant.
Because of this, it is impossible for you to have all three values where you want them to be. You have to pick whether to change the orbital radius, the orbital period, or the parent body mass.
If you change the orbital radius, to orbit much farther than a million kilometers, but have the specified orbital period and parent body, then it will be in a similar situation as Iapetus, but a little closer. Iapetus is tidally locked to Saturn, so it is safe to assume that another moon out there would also be.
If you change the orbital period, to orbit more quickly, but have specified orbital radius and parent body, then that is similar to Titan. Titan is also closer to what you want in terms of size, as it is larger by volume than Mercury, but it still is tidally locked, so any other moon out there is probably still tidally locked.
If you decrease the mass of the parent body, then there are no similar examples because there are no objects of that size to look at in our solar system. However, the "moon" would, assuming the same density of Earth, have a mass of 4.0 * 10^25 kg. In this case, it wouldn't be a moon, it would be the planet of this system, and the gas giant "planet" would be its moon, and this system would resemble the Pluto-Charon system.
Unfortunately, none of those situations give you a moon that isn't tidally locked, which is what you requested. However, there is one alternative which might work for your story:
Mercury is close enough to the sun that tidal forces should dominate its rotation, but it has a high eccentricity of 0.2 that prevents true tidal locking. Instead, Mercury has a 3:2 spin-orbit resonance. Your moon could be moved to a closer orbit, so its orbital period is a few days, and then given some orbital resonance due to a high eccentricity. If the orbital period is 60 hours, then a 5:2 spin-orbit resonance would be appropriate for a 24 hour day. Now, this will disrupt the wanted orbital period, and the distance will fluctuate quite a bit, but it will have a moon near to the gas giant with a 24 hour day and a longer orbital period.