Seriously, Kup, what isn't a retcon about Wolverine? Even the fact that his adamantium claws are part of him at all was a retcon - they were originally supposed to just be part of his gloves. He was initially meant to be a wolverine (yes, the small animal) that had been mutated into a young, agile human and wore gloves with retractable metal claws. Who'd pay to see that movie? (Okay, yes, I'd pay to see that movie.)
Personally, I think having bone claws makes more sense than them being added by the Weapon X programme (which was itself a retcon). Plus it made for a great surprise climax to Wolverine #75. [I also like the fact that the movie is using Grant Morrison's Weapon X is a Roman numeral idea, i.e. in the comics, Wolverine is Weapon X (Ten), Captain America is Weapon I (One), Fantomex is Weapon XIII (Thirteen) etc.]