Hi,
(if I am not wrong), there is no direct way to apply a (single stand-alone) raster function by arcpy - and thats what the convolution filters are. But this doesnt mean there is no way to do it. What you will have to do is "wrap" this raster function into a function template file (see here how to generically create one or here on how to export them) and then use the gp-tool "Edit Raster Function" to apply the function to a raster.
If you want to maintain this outside an mxd/layer you better put your rasters into mosaic dataset(s). There you can apply function chains on a single raster basis, by default for all or provide many different ones (Raster Function Templates) for the user to choose from.