I'm new I get it, however I researched this issue because I was concerned about it due to the fact that I'm looking seriously at buying a used 2003 WR450F here locally. I just got off the phone with Yamaha and here's the deal:
This issue was fixed at the factory on units (last 4 of your vin) 2694 and later
The actual TSB number is M2003-007A
And your SOL on getting it done for free under the TSB as it has expired.
For the record Yamaha customer relations was awesome.
I lucked out at unit #3000, well I think I lucked out, we will see when I look it over today. I'm anxious to get rockin on my SuperMoto project.