I had an overnight in August at the GH Bangkok and due to our early flight (early enough that the lounge wouldn't be open in time for us to visit) and we were granted continental breakfast in our room. Great spread of food, and since we were in a huge suite for the night, we actually got to use the dining table

Just checked off what we wanted on the door hanger and plunked in a sufficiently early time. Note that the Grand Lounge staff placed a special sticker/stamp on the door hanger which I think indicated it was free.

Edit:
And so it is clear, I didn't inquire about it. I did ask what time we needed to leave for the airport and what time the lounge opened for breakfast. From that, they were able to extrapolate that it wouldn't work for me and offered room service instead.