Round corners on custom shape

It would only take a moment to build it using the Rectangle shape tool.

 Create two rectangle shapes and round the corners.

I used the Move tool > align to center them.

Use the Pen tool to add a point for the point.  You can see that I snapped a guide to show me the centre and where to place the new point.

Use the Pen tool to delete the front corner points, and adjust the point radius.

Opt click the point point to make it a sharp angle.

Select both shape layers and merge them (Cmd E)

And merge the paths in the Options bar

That's less than a minutes work, and you can save it to your Shapes library