In my case everything was always mailed to me (my home address) but I have friends that got certain things like Advance parole and working permits through their lawyers.
It depends on the way your attorney filled or presented the application forms.
I think all green cards are sent to primary applicant's home address though.
Just wanted to tell you also that dont worry if you dont get welcome notice. As long as you get your green card, that's all it really matters.
In my case, we got emails first, then approval notices, finally green cards (like a week later) no welcome notice.