[pvanroy]

Yes, it's a Bf 109 E with a Fieseler-type intake, mostly seen on the 109 T, but also known from some late production E-7 aircraft. The exhausts visible in the photograph further confirm it to be a DB 601 engined E model. Likely the same aircraft is also visible in the background of the 109 G image shown in the same post. This aircraft in the background clearly is an E, as it shows the square wing tips and braced tailplane.

The round hole inboard of the MG FF/M cannon likely just is the opening for the MG 17 gun that armed the E-1, E-5 and E-8 models. When these aircraft were rebuilt to E-4/-7 standard and received MG FF cannons, the hole for the MG 17 gun was simply blanked off with a round metal plate - this is visible in quite a few photographs of cannon-armed E airframes.

As far as I'm aware, the MG FF and MG FF/M didn't require shell ejection ports - these weapons used drums, and the empty casings simply remained in the drum.