My son was born at 28 weeks and was under 2 lbs.
He didn't do anything according to the "book".
He wouldn't crawl, and when he finally did it was to crawl 2 paces to the nearest object he could pull himself up on and stand.
He didn't talk until he was about 2 1/2, he imitated noises and we did hand signs to ease fustration. But when he finally started talking though, look out, it was like a dam gave way.
One thing I will say, take everything the "professionals" tell you with a grain of salt, they may know kids, but they really don't know "your" kid. For the first year I really can't say I heard anything hopeful or promising from any of them, just imformation about all the learning disabilities and development problems he would most likely have due to his prematurity.
They were all wrong.
He just turned 12 this month, doing great so far in school, and obsessed with computers & video games like the rest of his friends.