Bucks will sniff its a way to identify other deer. As for the spar session was most likely a play thing. Did you notice if they was just going at it lightly or a death bought? Rut aint till last Oct early Nov here and thats depending on the weather. Seeing only yearling bucks with does riht now. All seem to be in batchalor groups still.
Not to much funnier thing to watch than 2 young bucks furring up and sparring. Funny as hell. Even funnier when the Big ole Omega Doe starts whompin on the lil bucks chasing them out. Watching the confused, bewildered look on that lil bucks face when she hoof whacks that lil rump!!!
When placing a trail camera don't just look for a well used trail. What you want to do is look for a freshly used trail off by itself that goes from a north facing ridge, thick forest, brushy knob or some other similar bedding area to a food source. Don't forget water sources. Especially in the summer months the deer need water so look for a good trail going down too a creek surrounded by thick cover and place the camera 100 yards up from the water source.
Scent control is very important...