That's about right.
When 10.5 slipped from its original release date of Feb 2007 I figured it would be ready for release by March of 2008. Instead Apple released the beta version in October of 2007 to people eager to pay for the honor of beta testing.
That's a bit rich, even for Apple.
Apple managed to beat my prediction by about two weeks -- so maybe all those unwitting beta testers helped move things along a bit. Based on the many fixes in 10.5.2 it looks 10.5.3 will be the release I'll upgrade to -- the first service pack after the true "gold" release.