It's a (dirty) Mopar Rat, top to bottom, front to back, cross-ram

I believe the "short" long rams don't have that long crease between the paired runners.
Yep. The original long rams had a full length divider between the ports. The intermediate version (prior to the max crossram) had the divider about half as long, to help top end power. (the original long ram is torque, only).
The long ram and short long ram are visually identical..... except for the divider crease length.