Shower installation with copper piping?

So, I'm putting in a new tub/shower faucet in our bathroom. I've had experience soldering pipes together, but I've never had a need to use dielectric fittings. The faucet I have says to only use copper pipe (makes sense since the mixer is copper), but the tub spout and shower bend are stainless steel. I've read that stainless steel is a natural dielectric material, but is it really safe to directly connect my copper piping to the stainless steel fixtures without some kind of insulator between? Thanks.