No way of knowing sadly.
I've ordered a new chain anyway now.
Yes, definately worth having a chain tool. I'd have been well and truely buggered without one on sunday, 20 miles from home.
There is if it's a shimano type. The pin looks different. It takes a bit of squinting at a clean chain, but if you can't find an obviously different pin, then it was the joining pin that went.
I once fitted an SLX chain on Cubester's Ragley using the original link pin, then had a change of heart. It took only a few minutes to find the pin and break it out again