No, you have to take part in the swim to touch the dolphins. However, you can stroke them at SeaWorld.
Wideeyes - you say you don't swim, but I wouldn't let that bother you if you really want to do the dolphins. I can barely manage more than a yard in a swimming pool without sinking (even if I thrash about with all my arms and legs!), but I still did everything at DC. I wasn't sure at the time of booking (DW had to persuade me) but I'm glad I did now.
The life vests they give you are very bouyant, and you can always opt for the full wetsuit (like I did) which is even more so. Even then, most of the dolphin bit takes place in shallow water - you can just about touch the bottom with your feet if you get nervous.
There is one bit where they offer you the chance to do a "dolphin pull" where you grab on to the fin and it pulls you round a lap of the deeper area of the pool, but you can opt out of this. In fact, as I was the only one to opt out in our group, the trainers arranged for me to get a 'mini-pull' in the shallow water, which I thought was very nice of them.