IF, your grandmother had bought a life insurance policy, then most likely was done (when) you was a baby, that is for a small amount. My parents bought one for me and my 2 siblings for $1,000 (each) that at age 21 was paid up, then my mother gave to me to keep.
Today, at age 64, the policy is worth $3,500, so the value went up $2,500 after 64 years from when it was taken out.
Is your mother still alive? If so, my guess (if) your grandmother had in fact taken out a policy, she would have informed your mother of this. Why not ask her? After both of my parents died, I still have paperwork lying around that I could have gone through to see what my parents had or not. Now, if in fact she had a policy, would guess your mother or whoever went through her papers, (may) have found this policy or not.
But, if you don’t know (what) company this is, then no there is no way to find out.