Even before the question was asked, developer Marvin Weissberg answered: "I think everyone should have a park." Then the man who has started the Flour Mill redevelopment near the Georgetown waterfront got serious about the legislative proposal of Sen. Charles C. McMathias Jr. (R-Md.) to make a national park of the Georgetown waterfront from the C&O Canal to the Potomac. "Most of the people living in the Georgetown enclave do not look into specific plans of waterfront developments and tend to shoot from the hip without giving enough thought to the matter," Weissberg charged. The developer wants to build 74 apartments and 120,000 square feet of office spaces on the old flour mill site between the canal and K Street.

Michael T. Rose, the 34-year-old Maryland home builder who was shot in the back recently by a young construction superintendent, continues to receive therapy at Doctors Hospital in Lanham. Rose, who is waiting to recover from waist-down paralysis, said that the superintendent, who also injured a cement contractor, had no grievance but was suffering from personal pressures. Rose has vowed to make it back to work.

Thomas P. Turchan Jr. is turning the former Moringstar Elks lodge and an adjacent house at the southwest corner of 15th and Q streets NW into a complex of eight condominium apartments priced from $53,000 to $84,500. The one- and two-bedroom units will all have fireplaces. One of the Morningstar Lodge apartments will have three levels, he said. The units are expected to be ready to live in this spring.

"Energy Conservation & You: a Housing Energy Primer" is available for $5 from the U.S. League of Savings Associations, 111 E. Wacker Dr., Chicago, III. 6001. The 47-page booklet gives energy-saving tips and also explains energy, the relationship of heat and humidity to comfort and how to make existing homes more efficient.

SHORTLY: Marshall B. Coyne is renovating the building at 1507 M St. NW. He bought the medium-rise former office and apartment building for $400,000 in July 1976 from the National Education Association. Coyne said he is spending a bundle to create 48 efficiency and one-bedroom suites in the old building but does not know yet whether or not it will be "related" to his Madison Hotel on the opposite corner of 15th and M. ... Despite the snow and cold last weekend, the Yeonas Co. attracted 500 persons to the opening of its Wolf Trap Green houses off Rte. 7 in Great Falls. Lord & Taylor furnished the models. Salesman Rocco Nocera said that three of the houses, which are priced at $127.500 and up, are already sold. Seventy-three will be built on half-acre lots.