Yes, that's the point. They share some aspects of their class position with labour, and some with capital. They are in between the two: a middle class.

A manager shares the interest of getting the most out of the people reporting to her and wants to press them to work as hard as possible, because that's how she gets her promotion, so she shares that interest with capital. But also she is working for a wage not making profits on ownership so she shares that with labour.

A sole tradesman doesn't have a boss telling him what to do, he only has to care about making a profit and so worries about costs of inputs etc. just like a capitalist. But he has to do his own work he doesn't command others to do the work for him and just collect the excess value from their work, so in that he is like a worker.