Yes; they are often planted upright, what's oblique about mass planting of cordons are the rows they're planted in, which are usually at an angle, depending on the aspect of the area in which they're planted, though sometimes they are actually planted at a 45 degree angle, more info below

https://www.rhs.org.uk/advice/profile?PID=87

In some areas, they are planted at an angle pointed north to take advantage of the angle of the noon sun in spring and fall, hopefully extending the season, and ripening the fruit better. In hot sunny climates like mine, cordons are rarely used.