Scanning the Wikipedia page for 5-HTR1A, it looks like most of the studies were done in the first decade of the 21st century, when the candidate gene (https://en.wikipedia.org/wiki/Candidate_gene#Criticisms) approach was at its height, before it became known that many of these studies were statistically underpowered and thus likely detecting noise. So I'd be skeptical of any associations between 5-HTR1A and personality unless there's been recent follow-up.