There are some 777 movements with defined interior angles, but there doesn't seem to be a pattern with the varying levels of finish
This example below, taken from the deconstruction by The Naked Watchmaker, showcases two defined interior corners on the 777 movement. While admittedly not the cleanest execution, shows some of the effort needed by hand to execute the anglage. The anglage also appears to be wider and more rounded.
Here is another example from SJX, taken from the 777 inside the relatively recent 5177 with blue enamel dial, released last year. This also exhibits the sharp inner angles.
Thus I find it odd how some variants of the 777, even till today, exhibit different levels of finishing (I believe that SJX photo that you've posted is taken from a Hora Mundi, which is at a significantly higher price point too!).
There doesn't seem to be a consistent standard or pattern in Breguet's case, unlike some other brands. For instance, Chopard differentiates their movements as different cal., with the 1.96 being their most well-finished example, versus the other variants of the 96 which have less finishing and features (such as missing the swan neck and overcoil hairspring).
Nevertheless, regardless of the different level of finish, it is always nice to see that Breguet does put in effort to ensure the anglage is still finished to ensure that the machining marks are removed, or minimized.