No, Royal Enfield did not manufacture motorcycles for Harley-Davidson at any point. Royal Enfield and Harley-Davidson are two separate and distinct motorcycle companies with their own manufacturing operations and product lines.
Royal Enfield is an Indian motorcycle manufacturer that has been producing motorcycles since 1901. They are known for their classic and vintage-style motorcycles, often featuring single-cylinder engines and a retro aesthetic.
Harley-Davidson, on the other hand, is an American motorcycle manufacturer established in 1903. They are renowned for their heavyweight cruisers and touring motorcycles, typically equipped with large-displacement V-twin engines. Harley-Davidson has its own factories and facilities to manufacture their motorcycles.
While both Royal Enfield and Harley-Davidson have a long history and produce motorcycles with unique characteristics, there has been no collaboration or manufacturing partnership between the two companies.