Claremont intended for Sabretooth to be his father and laid the groundwork for it but he was never able to do the reveal. And when he was replaced as the driving force behind the character it was quickly shown that Sabretooth only thought he was Wolverine's father.
Of course, then you have the alternate X-men Forever title where he is established as Wolverine's father and the Ultimate universe where Wolverine is his father.
Thank you for your post. I guess I read the comics of an alternate timeline back in the days. Incredible there is also a universe in where Wolverine is Sabretooths father...