Is it possible to change the default color mode to Grayscale?

I have over 200 images that I have to export to BMP. Each time I select one and export it as a BMP, I have to select Grayscale.

Select Image/Export/Save as Type - BMP/Convert to Bitmap/Color/Color mode: Grayscale.

The default is Paletted. Is it possible to change the default color mode to Grayscale?