That is NOT an "E" receiver. Just a standard receiver.

The "E" receiver has more pillars, the trigger group is shorter, and moved back, the barrel doesn't have the same contour as the receiver where it steps down further out, like yours does. Th"E" receiver barrel steps down right after the receiver. You gun only has one roll pin holding the barrel in the "E" receiver has two pins. Your receiver has a recoil lug on the barrel, this was deleted from the "E" receiver. I also believe that all "E" receiver guns have accu-triggers. That is all the difference I can think of right off the bat.