Only child, named Heir

Location: Missouri

So my Narc mother passed last June, she left EVERYTHING to my step-dad according to the Will (which was done by the hospital, 7 days before she passed after the stepkids had riffled through and claimed they couldnt find a Will) I was named as "heir" but nothing else. The house has been in my family for 4 generations, so I doubt even she was that cruel. I never got close with my Step dad or his kids, but according to their Probate Attorney, they seem to have big plans for selling the property. Was this a last a Screw You to me, or should I be fighting this?