These two shifters appear the same except for the HURST letters and one has fine threads. They're both from bench seat b bodies. Are either or both factory shifters?

They look like factory Mopar handles. Second picture is '68, first picture is '69 and later. There should be a number stamped at the base of the handle.

Could be an early(January) 68 and a late 68, they had both styles My 68 is almost 100% original its has the boxed style shifter

Yes, early and late '68. Thin font Hurst early style thick font later style.

Interesting. I have seen the '68 Inland which was used briefly at the beginning of the production run that I have always considered the 'early' shifter version. I have never seen the double stamped handle in a '68, only the single stamp. But that doesn't mean they don't exist.