Diamond Reo knowledge request!

I have a buddy who has an old abandoned truck on his land Was there when he bought the place a few years ago and he never gave it a second thought. Asked him for permission to get a look at it and figured with the right info, he could sell it as a parts or project truck. Anything you could fill me in on would be appreciated. What I know- it used to be part of a concrete company fleet, possibly a former mixer truck. Do not have any idea how long it was there prior to his acquiring the property. It is most likely a mid to late 60's. It has a 5x4 twin stick setup and what I believe is a Cummins engine. I couldn't read the tags real well, maybe you guys can zoom in and decipher something. I was the one that opened the hood to get a look at the engine, so it's been decently covered.