1972 big block mounts question

[General23cmp]

If I have the correct 1972 big block towers on the frame and the correct brackets for the engine, will 1973+ clamshell mounts work? They look almost identical from photos, especially their bolt pattern, but their two raised bumps on the engine side look a little different.

Are 1972 BB clamshells available from auto stores? I imagine the brackets are the difficult part, as the rubber mount is typically considered replaceable.