Originally Posted by va_dude
well if there's a way for you to get your approved labor certification doc, or even the copy of the filed labor application; then definitely get it.
The labor app has the exact job description too. So if you do use portability (ac-21) it'll help to match it with the job specs of the new position.
Read it properly before you jump. When there is no I-485 filed, where is the AC21 coming into the picture.