I think she is!
I was going to write an entirely different blog post today (it will wait!) but this morning I've heard Inds making the familiar foghorn noise several times. It's fairly unmistakable.
She won't go off to stud this cycle, after being on Ovarid you are supposed to let them have one complete call before going. But she should yowl for a week or so, have a week or two off and then call again- hopefully.
We're in for a noisy few days!