No, currently in vanilla Minecraft dinosaurs are not in the game. This means there are no spawn eggs for them.
Minecraft originally came out with spawn eggs in a pre-release - 11w49a. The update was for Minecraft 1.1, in case you are looking for an actual Minecraft update release.
You can find eggs, those can spawn a chicken but not all eggs do, or load new chunks and they will spawn, just not where you want
You can't. They can only be spawned in by a player in creative mode. (Although some mods do add crafting recipes for spawn eggs)
If you mean "throw" like with chicken eggs, then no, you can't.