1976 Riviera or electra oil pan??

So I have a 1967 buick gs400. My dad many to many years ago out a 1976 buick 455 engine out of a riveira or an electra. It was too long ago for him to 100% remember. I need to replace the oil pan as this one was dented. How can I tell if it's a riveira or electra? I searched and I guess the riveira is different so does anyone know a way to tell?

 

Is the sump in the center or at the rear of the pan? Post pictures here for verification.

 

I can't take a picture at the moment. But it is rear sump, the drain plug is on the flat surface, not side or angled, the rear is like a half circle where it mounts to the transmission and the front is more flat but the lip in the front where you bolt it is at like a 45 degree angle or so

 

Electra or any other 455 buick with a single exhaust crossover notch. The true dual exhaust pan doesnt have this and the RIV pan has the center sump to clear steering linkage. Hope this helps...

 

Thanks I stopped by TA performance and they sorted me out. I appreciate the help.