No, It isn't.
If Cracker wants I can update it
Funny thing is, I started updating it last night. But then stopped as I didn't think anyone would download it..
When you get a 404 etc, it shows the error in the forum template.
Ah, okay. I'm planning that for my Google SEO plugin too (404 page enhanced with Google 404 widget, also gives 404 for MyBB invalid forum / thread / etc errors that currently are 200 OK).