Window AC Unit Part question

I have a window ac unit that was given to me a few years back. It is a Carrier Model#Kca008101p, it did not have the side flaps that slide in the window sill. The past few years I have just used it in the spare bedroom where the windows were smaller and I was able to improvise. This year I want to use it in my master bedroom since the Carrier is a higher btu and more inline with the size of master bedroom. The rub is my windows in the master are wide windows and I really need the window side flaps.

Any ideas of local places where I can get replacements? I have only seen the inserts at home depot/lowes though I could take another look.

http://www.whirlpoolpartsonline.com/index.php?main_page=part_finder&model_num=KCA008101P&model_id=155125&manufacturer=

Looks like you’d need 17, 20 and 21.

I would mount your AC then fill the openings with cut celotex. You don’t need to get the flaps. They provide no support. Also, they don’t insulate we’ll either.

Or even at the very least just some plywood or similar. Should only be < $10 for either solution.