78-80 CR250 seat mounting

Hey guys I'm working on my C&J framed XR500 project and need a favor. The frame uses CR250 components. I picked up brand new aftermarket seat base, foam, and cover. The seat base comes with the 2 rear mounting tabs, but nothing for the front. Can somebody post a pic for me that shows the front mounting tab/bracket. It's probably "Z" shaped to fit under the frame crossmember, But I'd like to see a pic to get it right. The parts diagrams don't even show it.
thanks