Not sure if my puppy has started losing teeth

I have found a very small dark beige coloured thing that might be the size of a grain of rice,m and very hard.

Could this be a tooth my puppy has lost? He is 12 weeks old. Is he at the correct age?

If his teeth snapped off without a root is there any way you can tell? He doesn't seem like he is in any discomfort or anything. Still eating and drinking normal.

He is at the age where he just chews on anything.

He is due for his next vet visit in 14 days.

Unfortunately I can't attach the picture I took.