In summary my answer would be I'm 99.9% certain that Laborian is intended to be a fictionalised version of Asimov, but it's not possible to be completely sure. This would change if I could find a statement by Asimov that this was actually his intention, but failing that, the 0.1% of doubt remains. Wikipedia is less hesitant, stating:
In the Hugo Award-winning novelette "Gold", Asimov describes an
author, clearly based on himself, who has one of his books (The Gods
Themselves) adapted into a "compu-drama", essentially photo-realistic
although this assertion is provided without a citation.
Firstly, the sci-fi story "Three in One" discussed in "Gold" is clearly the same as the second section of "The Gods Themselves", Asimov's novel of 1972 - the characters of a Parental, a Rational, and an Emotional, together with their behaviors and appearances put this beyond doubt.
Laborian also describes his books as "I never have any sex in my novels beyond that which is absolutely necessary and then I manage to refrain from describing it... I think that readers find its absence in my novels refreshing; at least, my readers do", which is commonly remarked about Asimov's works. Another common point with Asimov is that Laborian says his work is mainly conversation-based, rather than descriptive.
These points make a convincing case for Laborian being a version of Asimov. However, he is described as:
dark in complexion, crisp curly black hair, looked as though he needed
a shave, probably looked that way all the time, prominent Adam's
apple, small scar on the right cheek, dark brown eyes rather large,
and his only good feature.
which (to me anyway) doesn't seem to match the physical description of Asimov.