I would say yes. A first 74xx to provide the sink capability, then, because that inverts the polarity, another is added to get it the right way again.
Why not use the optocoupler on both the input and output?
An opto for output driving could be used if the rise and fall times meet the MIDI specification, but it's an expensive component compared to a simple transistor. You also have to provide enough current to drive the LED but limit the current to prevent damage. Of course a transistor needs a base resistor. A logic gate is much easier and why they probably got used.
There are probably hundreds of different ways to do it but what tends to happen in practice is people don't fully understand the big picture so slavishly follow existing designs which get copied and tweaked. Why it's being done that way or why one component is used rather than another gets lost to history.
Using an FT232BM as here, it seems there is no need to use any output buffering. However, using a buffer does add a degree of separation for an adverse event that might damage the output.