I guess you're right; certainly the script seems to work that way. But there are a lot of silly things - why do Cylons glow when they have sex? That's something you ought be able to find. How do they upload and download? There should be a wireless system in there (whoo-hooo! A direct link to the OS!) that you can find and play with.
Also, they seem to be stronger than humans of the same mass - their muscle tissue should be different. Apparently they don't have the same need to eat or drink we do (although the Leobon seemed to enjoy his meal... which Starbuck thought was wretched) - they must have an internal power plant. Looks to me like there are a lot of basic, internal differences that would ID 'em.
All of those things coulf be done via biological mechanisms. For example, strength is neuron as well as muscle dependent. Most people are far stronger than they realize, but their brain inhibits using that strength. If you weight train for the first time in your life, most of the gains come from overcoming this neurological inhibition. Only after that can you start to lift to gain muscle mass. About the glowing spine, that would also have a biological origin. It doesn't take a lot of a material to bioluminesce. Also, the Colonials would have to know it's there to look at it and the chemicals responsible may be the ones Baltar's test will detect. Wireless is simply radio communication. Again, it may not be a specific neurological structure, but the way their brains can generate a signal - a synchronicity of activity and not a dedicated transmitter. Once you get down to manipulating things on a cellular level, you can get away from the constraints of bulk technology. Biological cells can be thought of as natural nanotechnology. Eating and drinking, plus bas metabolism can also be controlled neurologically. The cyclons either turn off their hunger receptors or they ignore the inputs. Humans can be conditioned for this. THe cyclons merely know the biological mechanisms and can exploit them at will. THey are like humans, but can fully control their bodies in a way we could only dream of. But also look at what they don't have. They have no emotion - no passion. Only Boomer developed that as part of an experiment and love turned out to be the needed emotion for conception. Even another No 6 commented on what it must be like to feel passion. They are lacking that and they know it. That's what keeps them from being human and they are trying to overcome that gap.