...Looking at the pix of your kit - it looks like an early 60's M3 and with the L seal intact that means that it has been "unserviced" for close to 50 years. Most of us dont go that long without check-ups!!!
Before you send it off, shoot a couple of rolls of film and check speeds, framing, focus and if you find something odd, tell that to whoever is going to service it. Most likely you find the slow speeds a bit off, 1 sec closer to 2 etc. You can also have a bit of "drag" on the shutter where the second shutter curtain takes its own time to close.
You also have one of the great lenses that Leica made, a DR Summicron 50f2 - It is still one of my favourites today - even compared to all the new and splendid glass available. Sharp and one of the nicest tonal renditions of any lens. As it was a bit of a speciality lens when it came out, they tended to be put together with more care than the "regular" 50's. The little ball that provides the "interlock" for the close range occasionally gums up and can make it difficult to mount and remove the "goggles" - but that usually can be cured by doing it several times, just to get the grease loose again.
It is always a pity that inheriting something usually means that someone has to die, but as stated before, use the camera in memory of your grandfather and he had very good taste in equipment too.