Subframe connectors for a driver/cruiser, necessary to weld to floor?

Sub frame

BFBC12F6-6FC3-4CFB-85C6-BBB23DB47B00.jpeg

ECFB3E3F-77A5-4596-9E47-DFA107009DD6.jpeg

8DCB4B32-CA8F-40BC-9EDF-3A9AD250F182.jpeg

CA9E0A68-C937-4E51-B752-5545D8D63BF0.jpeg