Is it unlikely to show onset of first symptoms of hsv 1 or 2 six weeks after initial (low risk) contact?

Up to half of new genital HSV infections are asymptomatic, but many of these are in people who don't pay much attention to their genitals. Most people concerned enough to be worried and regularly examining themselves probably will have symptoms. So your lack of symptoms plus low risk of contact strongly suggest you were not infected.

If you show negative antibodies to hsv after 3 months I think you could then conclude that you were not infected.