Airbubba, as you say, after 1500Z (in fact after about 1430), the aircraft would be issued the noise mitigating SID via the West Lamma Channel.
That crossover period is a hazard in that aircraft cleared much earlier (particularly cargo whose off block time has a large degree of variance) may be initially issued the normal OCEAN SID, which subsequently is changed to the RASSE SID if they will then depart after 1500. I haven't heard the CDC playback so that would be interesting to confirm that as a first point of possible confusion.
The RF SIDs were designed to mitigate the spread of noise around the Ma Wan area, however ATC is not aware of all the different company's FMS capability. We have an agreement with CX, that all 777 and -8 will automatically be issued the RF SID by default. (there may be a couple of others now as well but not 100% sure). It is available to other operators on request as well and several do so.
The rub here is that to Clearance Delivery, this is a Cathay callsigned flight and the fact that it is being operated by Polar/Atlas is not differentiated.
Is there a common understanding with the wetlease crews that they will receive this automatically and is it a foregone conclusion that ALL 74-8's are RF capable?? (I presume so but are there different user-spec available?)
As you also indicate, the correct charting format of PORPA as fly-by is used in the RF chart. The path terminator coding for RF is necessarily different as the requirement to fly a fixed radius from a centre takes over immediately at the fix which actually requires the aircraft to commence roll-in just prior to PORPA.
Just looking at the initial track after the first turn, it does appear to be direct to RASSE, which makes me ask the question if the aircraft was RF capable and coded with the RF SID.