It's impossible to know if all progressives are Hegelian, unless they specifically say so.(which I haven't seen) But as I blog more about these people you may notice the words/phrases 'germanic' and 'prussianism'(and other variations like it) repeately show up, that's how they described it in their day. The "Making it customary to utilize the collective knowledge" (to borrow a phrase from Dewey's discourse of prussianism) ideals of germany is where a large portion of the roots of progressivism ultimately come from.
Charles Merriam, In his book "American Political Ideas: Studies in the Development of American Political Thought" writes this: (page 373 - this is written glowingly)
One of the striking features of the last half century in America was the greatly increased attention to the scientific study of politics. In the last twenty-five years, particularly, this tendency was very clearly marked. The foundation of systematic study was laid by Francis Lieber, a German refugee, who came to America following the Revolution of 1848, and was for many years a source of inspiration in inquiry and a teacher of methods of investigation. Following Lieber came studies of the type of Mulford's "Nation" (1870), a striking illustration of the intoxicating effect of undiluted Hegelian philosophy upon the American mind. He expounded an entire dialetics of democracy in the abstract and theoretical form of the German mid-century "metapolitics". Brownson's "American Republic" was notable as a careful exposition of American political doctrines.
Beginning about the 1880's there was an impetus given to the systematic study of political problems which continued undiminished in force down to the end of this period. Woolsey's monumental work on political science appeared in 1878, Henry George's challenging "Progress and Poverty" in 1879, Wilson's encyclopaedic "The State" in 1889, Bryce's comprehensive and illuminating work on "The American Commonwealth" was published in 1888, and Burgess' formal treatise on "Political Science and Comparative Constitutional Law " in 1891.
Notice that key word "democracy" again there. It's a rallying cry for progressives and they have a completely different definition for it than most of us do. If anybody reads these books and finds useful information to further learn progressive ideology, let me know.
It should be noted that a very well known Hegelian in history is Karl Marx.
Keep in mind, this is the same Charles Merriam who wrote that The individualistic ideas of the "natural right" school of political theory, endorsed in the Revolution, are discredited and repudiated..
Natural rights, dead and repudiated. Who am I to argue?