Not that it matters, but the reason MS recommended a 16-bit installer was that non-Intel Windows NT variants could run 16-bit x86 software via emulation. Windows software that ran on multiple architectures (what little there was) typically had a tiny 16-bit x86 setup program that checked the architecture and launched a native 32-bit installer.

Edited to add: x86-only software had a similar tiny 16-bit setup program that launched the 32-bit installer on x86, and displayed a helpful error message on other architectures. This was done because Windows had a piss-poor error message if you ran a 32-bit exe on the wrong architecture.