How to find out per acre mineral rights values from 1976

Oklahoma Mineral Rights Grady County, OK
1

Six months ago I sold my shares in one area in Grady County. My tax accountant needs to know what those shares were worth in 1976 when I was gifted them by my generous parents. So far, we cannot find the original deed that my parents must have possessed. Any place that might have that information?

2

idocmarket.com is the online files for Grady. Not sure if they go back to 1976.

3

I have been told that in Grady County you should use a company called JEROCO located in Chickasha.

4

Yes, we have been in touch with them. Thank you.