is there such a thing as a single lake chip for Sam Rayburn? I have seen a lakemaster chip on a Friend's boat but I can't find out where it came from(It was given to him) is there a way I can find out the numbers or something from the chip or maybe a place where I can order a chip (I will still have to have some sort of numbers to order it)

Go to humminbird site and look at links. There is one, cant remember what they call it, but you can purchase a download for specific lakes and load it on an sd card.

I looked at Humminbird and Lakemaster but couldn't find it

Download and install Humminbird Chart Select to your computer.

With that software you create an account to purchase and download a single body of water that is HD.
To do that you have to put an Encrypt folder on a blank formatted memory card of 32 GB or less in capacity.
You use your Humminbird unit to put the encrypt folder on the memory card.

The body of water file has the contour map, several years of satellite overlays, USGS map overlay, and SmartStrike you can add to the purchase.

Thanks