Some 10,000 post offices are to be emptied by the Postal Service in the next few years in a consolidation program, and a task force on historic preservation yesterday recommended that General Services Administration look into recycling them into federal offices and retail shops.

Sounds like an obvious recommendation, but the preservationists, in a three-day meeting here at GSA head-quarters found that a primary problem is that one government agency doesn't always speak to another.

"For instance, the Bureau of Standards has done pioneer work on how existing buildings can be revised to meet new standards for access to the handicapped, structural and fire safety codes," said Rogers Lang, a Boston architect, and a panel member. (He lives in an 1894 house himself.) "Yet not all government agencies have seen the bureau's findings."

In other recommendations: "GSA needs to pay more attention to how government buildings are maintained," said Jerome Pratter, the meeting chairman. "And our group said the government should be permitted to sell excess government buildings not to the highest bidder, but to the organization willing to accept a covenant ensuring historic facades."

Pratter said the group in general applauded the work of GSA Administrator Jay Solomon and urged the agency to expaned the program of preserving old federal buildings and finding new uses for them. They urged an educational campaign through GSA and the government to make employes aware of not only historical buildings but buildings significant for other reasons - architectural distinction, for instance.

The panel also urged that GSA work to preserve individual buildings and the street setting.

Final recommendations of the panel will be issued in three weeks.