After looking at Iowa's preliminary notice requirements - I would expect that, particularly on larger projects, prime subcontractors would almost always have provided that basic info (name, address, and phone) to the GC on behalf of their second-tier subs. Assuming they didn’t, the Iowa statute (572.33 sub 2) appears sufficiently vague to cover just about any single correspondence the second-tier sub would have with the GC (submittals, statements of value, invoices, heck…even email signatures). Wouldn’t you agree?