Not at all. Having seen the claim, we now ask: "Why is Paul making this claim?" "To whom is he making the claim?" "Who is this 'Lord's brother' and why is he so important?" etc...
It isn't a case of just taking it at face value because even if it is false, the claim itself can teach us something.
Not if the whole thing was invented as a hoax hundreds of years later, as dejudge proposes.
This is actually the same claim that we have been over literally hundreds of times before - the claim that someone named James was the actual human brother of Jesus.
But what is undoubtedly true about that claim is that all the evidence shows that it is far more likely that the remark in Paul's letter was never meant to mean a family brother at all.
Because firstly, Paul uses the terms "brother", "brothers", "brethren", "sister", "sisters" far more often to mean only brothers and sisters in faith, and not family members. So just on that statistical basis alone, it is far more likely that the line "save James, the Lords brother" only meant a brother in the faith.
Secondly - that same James was supposed to have written his own gospel. But nowhere in that gospel does he ever claim to be the brother of Jesus. In fact he never claims to have ever met any human Jesus at all.
We could also add that those five words "save James, the Lords brother" are positioned at the end of an otherwise completed sentence. I.e. they are presented in the form of an afterthought, as if the writer had forgotten that he had met "James", and later remembered to add that remark. In fact the proceeding words actually say "other apostles saw I none ...". So the addition is actually in the form of a
correction as well as an afterthought I.e. as if the original author intended only to say "other apostles saw I none". And then somebody has remembered that he supposedly met "James", and he adds "...save for James". And then after that, somebody felt that they needed to explain who this James was and added " ... the lords brother".
Though whether that was ever written in any original letters from Paul, or whether it was a later copyists addition, is of course unknown. Though we do of course know that the later copyists, who produced all the known extant biblical writing, certainly were in the habit of often making changes like that. In fact, out of 13 letters said to be written by “Paul”, about half of them are now regarded as complete fakes ... not merely filled with “interpolations”, but entirely “interpolation” from start to finish. And finally on that point - that one ultra brief remark of just 5 words "save James, the lords brother", was never again repeated anywhere in any of Paul's supposedly genuine letters.
And another point - in his book, Carrier says that all baptised Christians at that time, were said to be brothers of the Lord. That is, he says - the term "brother of the lord" only meant someone who had been correctly baptised in the faith.