Sorry for stirring the pot and them waiting so long to chime back in. The picture of the front of your engine is the one I was referring to. I've found several places, including Rock Auto, that also list the same style (rotation wise), for cars that I know to be reverse rotation pump cars.The cover you posted from Jegs is the one for standard rotation. It's a Jegs house brand, not Edelbrock. It's a "one size fits all" hodge podge evidenced by the drilled but plugged boss for a front dipstick tube. Edelbrock sells a specifcally reverse rotation cover. As you've found, there's a ton of variations in a SBF timing cover and it can real confusing, real fast!
You're right about the mounting face to the block and I apologize for causing the confusion if that's where you're sure it's leaking from. IMHO, it certainly could affect cooling. I'm a firm advocate of doing something once and doing it correct. Admittedly it's not mine but if it were up to me, I'd locate and install the correct one. Yeah, I'm OCD that way!
Regardless of intending to replace the cover with the correct application, I'd still check the old one to locate the leak source. As already suggested check for cracks.I'd also recommend a straight edge across the gasket surfaces to see if it was warped. Laying it on a piece of glass would be ideal.
Good luck!