Yes, but the Project Proposal IV was that which became the production version of the Me 262 not one of those paper proposals
Well if you make enough suggestions you might get lucky with one. Messerschmitt got lucky when Hitler decided that he wanted a fighter bomber. Milch's response to Hitler berating him in April 1944 about the lack of such an aircraft was, apparently (Foreman/Harvey), "My Fuhrer, the Me 262 was designed as a fighter in the first instance." This despite work on the fighter bomber variant being prioritised at Messerschmitt in December 1943.
Cheers
Steve