You will find all today's pseudo-Christian groups claiming to have their basis in first century Christianity and the Bible. The LDS make those claims and can produce a list of Bible proof-texts that appear (on the surface) to indicate that they have some Christian doctrines.
The way to go about ascertaining whether any group is Christian or merely pseudo-Christian is to try the test mentioned in the Bible in Jude verse 3. Christians of the first century were told to contend earnestly for the faith that was once for all delivered to the saints. In agreement, the apostle Paul told first century Christians not to be swayed by a different gospel, even if an angel delivered it to them (Galatians 1:7).
Any group that has new doctrines, different to the ones believed by the first century Church, is a pseudo-Christian group, no matter now many other doctrines it has that are soundly Christian.
The LDS and the Jehovah's Witnesses both arose in the 19th century, and both claim that the Church Jesus established became so corrupt, God had to discard it and raise them up instead, in these 'latter days'. They were given 'new light', new teachings, and their new writings had to be absorbed in order to understand what the Bible was 'really' saying. Of course, neither group thinks the other group is God's chosen group today!
Just ponder that and waken up to the need not to look at matters the way they wish to present them to you.