I think we all understand that when these believers in Christ the promised Messiah were saved and blessed for their unwavering faith, they were not reading the New Testament, much less the King James Version of it. (see first link below)
God is fully capable of preserving His word and interpreting it thru His Spirit speaking to readers' and hearers' souls, for all those who seek Him and submit to His unique authority spoken thru the scriptures.
There is great promise and hope for all who died believing in Christ, and for those who believe Him when He returns to take all believers to our eternal home in God's presence. (see second link)
Hebrews 11 - Faith in Action
https://www.biblegateway.com/passage...11&version=NIV
1 Thessalonians 4 - Believers who have died, and believers who are alive when Christ comes again:
https://www.biblegateway.com/passage...+4&version=NIV