A presidential commission studying the nation's more than 3,800 military installations is closing in on its goal of determining which ones should be shut down. Former Rep. Jack Edwards, the Alabama Republican who helps chair the 12-member panel, says it will meet its year-end deadline of recommending which bases should be closed. But Edwards said a final list has yet to be prepared for Defense Secretary Frank C. Carlucci. "People keep asking about a list and wanting to know how many bases, but we don't have a goal in terms of numbers," he said. "We haven't made any final decisions yet." Edwards said he doesn't know how many bases will be on the final list, but Rep. Les Aspin, D-Wis., predicted the figure will likely be 20 to 25 bases.