E-27 Transom Permutations
I have seen two versions of the E-27 cutout. The boat I used to crew on once in a while had one that was an "opening", i.e. the top was intact clear across, about a two or three inch section. That boat came with an A4, later replaced by the owner I sailed with, with a Yanmar one-cylinder diesel.
He also put in a removeable smoked acrylic fill piece into the transom opening. This could be easily slipped out for swimming access to the water (well, if the swimmer was not too rotund...)
I have seen many others with the outboard cutout, and the opening went all the way up both sides, for a complete cutout of the center of the transom.
In all cases, the finish gel coating indicated a factory option -- presumeably for when the buyer had not opted for the inboard.
Anyway, them's just observations "from the field."
Loren in PDX