Yes, it is a hand sewn buttonhole stitch. I have used it a lot in my sewing and to neaten or reinforce a buttonhole in knitting. It is used for other things besides buttonholes, some only decorative, and if you make the stitches far apart it is used along the edges of blankets or clothes and called "blanket stitch".
Here is a video that shows one. I have not watched it as I have a dial up connection and tonight it is moving so slow it would take all night to bring in this 3 minute video.
No joke. LINK
I did a Google search for "how to buttonhole stitch" and several things came up.
I wanted to mention that I have used the yarn I knit with if it is not too thick and a good thing to use would be embroidery floss in a matching color.