What is the difference between a Harley flstn and a Harley flstni?

When Softails were made both carbureted and fuel injected, the "I" at the end designated EFI. When all Harleys became fuel injected the "I" was dropped, since there was no longer a need for differentiation.

FLSTN is the letter designation for both the Heritage Nostalgia and the Softail Deluxe.