Answer
No. The centroid method is the only one implemented for SELECTPOLYGON.
However, a workaround is possible:
1. Convert the grid to polygons with GRIDPOLY.
2. Clip the resulting polygon coverage with the selection polygon.
3. Convert the selection polygon to a grid with the POLYGRID command. Use the weight table option as it is described in the POLYGRID documentation.
4. Process the grid to represent the appropriate mask to block out cells outside the area of interest.
5. Set the resulting grid as the SETMASK grid.
6. Create the final result with a Map Algebra statement similar to:
Final_result = Original_grid