Rear Sill Dranage

[leebie2811]

Hi my mate repaired both my rear sills but forgot to mention the sunroof drain pipe runs down into them probably why they always rot out.
Should I drill a hole in the back so they can drain out?

 

[elty001]

The original drains are along the bottom seam of the inner and outer sill sections.
I repaired my rear sills recently and i left about 10mm un welded on the seam and knocked a small chisel between the the two sections to replicate the standard drains.