The pan you have is a 6 quart over the counter that was sold in the Heavy Duty Chevy parts book only back in the day. Its a legit GM pan. They will fit 69 Camaro, Nova, Chevelle. The windage tray or baffle as they called it is part number 3879640 semi circular tray. These are very rare. They installed these pans in Giibbs high perf Novas and Camaro. Check out ebay, Chevy windage tray, there is one right now for sale. I just paid 400.00 for one on ebay. These parts are bringing in big money. The oil pan had a deep sump with one baffle design.