Well, first off, DD doesn't make the BI's, they're made by some offshore company (Phillipines, Puerto Rico?), so there was probably some kind of notice issued by BI, to all the distributors, that they knew that there was a problem and that they were working on it.
DD was probably the first US company to apply any kind of fix, WITHIN THE US. So there, the claim would be true.
You'll find that a lot around the US: claims to be the first... you have to read between the lines.
As for their tops, well, watercooling isn't anywhere near being standardized, so the block was probably working just fine, for 95% of the users. The other 5% is the users that use it in a weird way (big pump, hot water, weird water, who knows?). So DD makes a fix, and revises/refines their manufacturing process, to cover for some of the 5% of idiots out there...
And actually, we discussed the problem extensively here, and we found that there was no problem whatsoever, for practical purposes. It was strictly an esthetic issue.