According to text in the Bio, Lett-143 had two wives, one of which has apparently not yet been profiled. If that tracks with the name you got from a family bible, it's probably OK to add a profile for her and make the connection to Lett-143. If your data says that the wife who has been profiled is incorrect, she can be detached from Lett-143 on the edit screen, but before doing that, the communication guidelines would urge you to contact the profile manager and compare notes. The other possibility would be to leave a comment on the profile indicating what change you would propose to make, identify the source, and see if anyone reacts to that. If there's no immediate response, I would give it at least a few weeks before detaching a relationship, and try to verify what you found with some other source in the meantime.