Is marriage history a material fact?

[AmericanWannabe]

Pretty much due to my passing information and paranoid mood
from this forum to my aquaintaints. a person here gets nervous.
She had a unhaapy marriage and then divorced in her home
country. She married later, came to her husband in the USA
and got the green card. But she did not disclose previous
spouse's name on the I-485 applications. She did not
have any children with the previous marriage so there
was no such thing as suddenly coimg up the issue of
sponsing a child whose name was never disclosded before.

So should she amend her I-485 application file or not?
Or should she just treat like that marriage never occured
even in future N-400 form?

Is that a maerial fact (note no children from previous marriage)?