No, but Marx is no less valuable a 19th century thinker than Hegel, Mill, or Marshall. Many of his insights into the nature of capitalism remain just as vital today as they were in his day-- perhaps even more so. We are now living in, by far, the longest extended period of wage stagnation since the 1840s.
Obviously he was more influential on the 20th than the 19th century. Of course it is also hard to limit the discussion purely to economics when that is one area that has seen considerable widespread acceptance of the failures of application of Marxian philosophy by socialists in the 20th century which in turn fueled the late-60's / 70's New Left movement.