Salvation and baptism have nothing to do with dates.
It does when Christians are required to have the same mind. Christianity is not structured for everyone to go around believing and teaching to others whatever Bible interpretation they like. Dates was not the only teachings of CTR either. And, the dates were believed to be true at the time. Obviously you needed to believe all teachings of the org. Or at least submit to the authority of decision makers. 1874 is 101 years earlier than 1975 which ctr miscalculated but was on the right tract. 1975 is 6000 years after the creation of Adam based on 539. So is 607 and 1914 also based on 539. JW discarded the cross and other beliefs they later realized were false but the dates you mentioned are still significant 1874 was adjusted for the zero year and the 100 year error. There is a human element and tolerance in all of this which don’t nullify the truth of JW beliefs.
Also, at the time the JW were “Bible STUDENTS” which implies that they were only learning. —And doing it in an orderly way.