If the Royal Hudsons will have a Loksound 5 decoder and you have a LokProgrammer then you might be able to download the missing whistle and install it in a vacant sound slot. You should then be able to remap it to an unused function button.
Or, you could email Rapido and inquire and/or put a bug in their ear to include both whistles with the release. Now's the time to do it. Rapido seems to want to go the extra mile so I wouldn't be surprised if both whistles will be included.
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
I think the two Hudsons I have now have a choice of three whistles, I will check later. I changed one of them and left the other original. I really like the sound of the one I changed to, I believe it was the one it had while at the museum.
Brent
"All of the world's problems are the result of the difference between how we think and how the world works."