Does chipping indicate untempered glass?

[Kmore1219]

So the tank I have is fairly old and has chips in many places. I was thinking of drilling the back of it to do an overflow but can't figure out if the glass is tempered or not, then I realized all these chips along the glass. Would chips of this size be any indicator that the glass is not tempered?

 

[CodyRVA]

Why not test the glass and confirm if it's tempered or not?

 

[Supurderek]

Chilling can occur in both tempered and untempered glass.