Gil Hibben makes the knives for the rest of the movies. He sells custom ones $$$$$$$, or you can buy his designs from United. United cant sell them as Rambo knives anymore since the studio gave the license to another company. The other company makes lower quality copies of Hibbens knives without licensing from him.
The United ones are called Hibben followed by the film number.
I signed up without properly reading the intention and foundation of this forum as I noticed Jimmy Lile knives mentioned, I had a rough day and obviously did not do my research, I bought a original Hand Made Jimmie Lile Survival Knife and was curious what it was worth. I unfortunately have zero interest in costuming.