The deal is a take-over. Ownership was completely

transferred. The take-over would highly unlikely affects your GC application. USCIS or (DOL) generally would ask the sponsor to prove that it was the same company as the one on the original LC or 140. Take-overs, mergers and buyouts are normal and are the market trends in North America. Even if USCIS discovered that there were different sponsors for ur GC, an adequate explanation by the company attorney regarding the take-over would likely erase the doubt as long as the ownership was completed transferred.

If I were u, I would not worry about it as the lawyer might be right.

Disclaimer: FYI only, only a legal advice.