Its not very likely, but completely possible. Given the circumstances, I hope that is not the case this time. There should never be any question as to "if" they tied. Dogs should NEVER be left alone to tie unsupervised.
It puts both the male and female at risk for injury.
The questions you have asked are very basic concepts in regards to breeding--things that should be researched and common knowledge BEFORE you ever start breeding to begin with. These are not things that you just 'pick up as you go.'
Not to mention, your dog is 6 1/2 years old. She is to old to be breeding at all!