Drain Holes in Heater Channel Bottom

[Jam]

I had to replace the heater channel bottom plate,i got them at different places.The one on the right side has 2 drain holes,one in the front,and one at the back.The left side does'nt have any holes,are these drain holes,are they suppose to have a rubber plug in them.Where would you get the rubber plugs.I also had to replace the top of the heater channel,and it does'nt have the 2 drain holes for the doors to drain.Would you just drill 2 holes.The factory holes look like a V.The water runs into these drains and into the heater channel,and out the bottom of the 2 holes in the heater channel cover.Is all these drain
holes necessary.
Thanks
Jam