Front sprocket issues again

[Cagey Thoughts]

Thanks for the post..... just putting my Fazer back together and was looking at all the mod ideas..... so really useful.
I may be wrong, but did  i read somewhere about a different sprocket being released by Yamaha that was indented to take a wider nut?  I think it came out as a 'service update' in 2005? 
The nut & washer kit went up from 9mm to 12mm on part number... 90891-10124, but I cant find the part number for the sprocket (if it exists)?
Only had the nut fail once since 2003... but.... belt n braces.... lol