You should check with the court in the county where your grandfather lived. If a will was probated there, a copy will be in the court records. There will most likely also be a procedure where you can ask to be notified if a will is probated in the future. If you are provided for in other ways, such as a beneficiary of a life insurance policy, the court will not know about that and you may need to wait until you are notified by the holder of the asset.
If there is no will, you may not be an heir to the estate. Generally, grandchildren are not heirs where there is no will unless their parent has predeceased.