Does This Add Up? (age Of Guinea Pig)

[Jane0101]

hello, today I started thinking about something when I read something that said that young male piggies dont have very visible testicles but when we got him he already had quite visible ones.
We got him in July, from the pet shop, being told he is approx 10 weeks old. He was quite small and I weighed him a few days later and he was 708 grams. He now weighs 1046 grams
He has grown.
I'm just wondering, does that sound right for his age? Did they tell me the truth?
I will attach a before and now picture of him. (First image is him now)

 

[piggieminder]

It sounds to me like he is older than you were told but I am very far from an expert. I am hoping that by replying to you your question will get bumped up and someone better qualified than me will be along soon.

 

[Swissgreys]

A photo of his feet would probably help too.
Young piggies (under 1 year) tend to have quite thin, needle like nails, ad older piggies have thicker ones.