If FCP makes you render, it simply means something about your media is different from the sequence you have it in. To avoid rendering, you’ll need to make sure everything about your MOVs matches your FCP sequence (codec, frame rate, audio settings, etc., etc., etc.) To determine where the difference might be, when you right click the FCP bin window there is a list of things you can have it show about each file and sequence (video codec, frame rate, aspect ratio, audio codec, etc.). Check all the pertinent ones then go down the list and compare the MOV file specs to the FCP sequence specs.
It’s important to note that all “uncompressed” MOVs (aka “none” codec) are not created equal … if the MOVs were made with one “uncompressed/none” codec and your FCP system uses another, you’ll have to render. For example, I ran into that when I first started bringing “uncompressed” MOVs from my Windows After Effects station into FCP since the Windows system was using BlackMagic Design “uncompressed” codecs and my Mac uses the AJA “uncompressed” codecs. I just installed the AJA codec on my Windows system, made sure the “none” settings I used to render from AE matched those I used in my FCP projects and voila … no more rendering in FCP. Similarly, you will have the same issue if both your FCP sequence and your MOVs use the same type of “uncompressed” codecs, but one is 8-bit and the other 10-bit.
I hope this helps!