On strong earnings from blue chip manufacturer Caterpillar, the Dow gained 62.19 points to close at 12,810.16.  In housing stocks, Equity Lifestyle Properties was up .10 percent, and Skyline Corporation gained .46 percent.  Others closed down or flat: Sun Communities was minus .72 percent, Cavco dropped .68 percent, and both Nobility Homes and Deer Valley were flat.  The Manufactured Housing Composite lost .50 percent to end the week at 1222.30.