Danger-Will-Robbins. If you're applying at a VC-funded company, there's a decent chance the HR person has no idea what the engineering culture is actually like. Don't wear the tie.

In every company I've worked for (pre-money startups, post-money startups, small public companies, 10000+ behemoths), the HR tech recruiters actually interacted with the team frequently and had a good idea how they dressed and behaved.