I don't have a backup because I didn't know how/was not in the initial procedure I found, but kicking myself because I know a lot better than that
I have save screenshots of the VO in the prior link - it appears that #0609 may be the production year as it is mid 2009.
No, the horn does not work.
EDIT:
Just seen your reply - will go remove 540/add 544 and see what happens