Rear wheel cyl gaskets??

I am trying to put my new brakes together while the 8 3/4 is out of the car. Pretty much new everything in there, when I went to put in the new wheel cyl I noticed that the old ones had foam gaskets in there that went between the cyl and the backing plate. I spent about an hour at the auto store trying to find them(I think they should came with the new wheel cyl). Can I put them on without the gaskets or does anyone know where I can get them. This is about the last thing I need for the brakes and then can take the rearend up to Nigels. Thanks!