In his section "Names Proper & Common Universall" he writes:
[...] And it seems, there was a time when those names of number were not in use; and men were fayn to apply their fingers of one or both hands, to the things they desired to keep account of; and that thence it proceeded, that our numerall words are but ten, in any Nation, and in some but five, and then they begin again.
So who were these dudes? I've heard of ancients counting in base 6, but never 5. Who was Hobbes on about?
Roman numerals go in steps of five: I, V, X, L (fifty), C (hundred), D (five hundred), M (thousand).
Hobbes isn't speaking about any specific group of actual people. This sort of hypothetical "man in wild", or man in a "state of nature", is common amongst philosophers and economists, who need to create an image for their narrative more than quote actual historical documents.
David Graeber's "Debt: The First 5,000 Years" thoroughly explores the phenomenon of creating the "ideal/idyll man" as a sort of concept to build upon without a necessary historical basis.