How to tell what version your Iphone 3gs is when you can't go to setting?

I'm trying to hactivate it and I can't tell whether its a 6.1.3 or what. I can't really do itunes because it just saids that it doesn't have a sim card please disconnect. Really lost…

If you connect it to iTunes, what happens? Do you have a chance to explore your phone? If you do, go to account or summary or some like that and see what detail it gives you. Another option is if your are planning to use this as a phone then obtain a sim (which should be free) from your carrier, install it, then set up your iPhone & then you should be be able to go into settings.