So, what is reality, if not the ideas that represent facts we think we know?
As an applied (non-theoretical) science guy, I tend to be a pragmatist, and a bit bored by the philosophical questions like, "what is reality"? etc.
As someone trained in the biological sciences, I know that animals likely perceive our World in ways that we cannot understand, ias t's so far beyond our senses. Homo sapiens are limited by our unique collection of sense organs and their capabilities, although we have devloped technology to allow us to extend our perceptual senses beyond our limited range.
As one example, only recently has man learned about long-range communication that whales engage in over hundreds of kilometers via the SOFAR channel, basically a "long-distance chat-line" for humpback whales and other marine mammals. You couldn't "hear" this going on, if in the ocean, as it's such a low-frequency; we have to imagine what it would sound like, but even there: it's only guesswork. You need to be a 10-ton mammal to "know".
Insect and bird eyes are tuned to vision in ranges we cannot naturally see, and while we can study and speculate about their perception, we cannot KNOW what that reality is no more than I can positively know what YOUR reality is.
Even human to human, we know that all humans perceive colors slightly differently (aside from the obvious protanopia/deutanopia forms of color vision defects), and some people even see colors very differently between their two eyes! Instead of color perception being a common perception, there's in fact significantly more variation in a human population than most people think about.
Point is, we ALL perceive reality quite differently, but you and I AGREE that whatever the color of THAT object over there may actually be (i.e. in terms of it's wavelength, as measured with a spectrophotometer), we agree to call that perception "red" (and protans are unable play the game: it looks black to them, although depending on the degree of their being affected, it also varies).
Are the ideas less real than the uncertain things they describe?
They are all uncertain, in the sense that the "reality" of an object's properties is dependent on what organism is detecting/perceiving them... A grain of sugar presents a different perception to an ant than it does to a human. Who's perception is correct, i.e. the "reality"? Reality is species-specific; hence humanoid "reality" not universal.
It goes back to the story of three blind men who encounter an elephant, and one touches the trunk and concludes it's a snake; another touches a leg and concludes it's a wall, etc.
Is an old model any less real than a new one?
Old models are refined to improve their predictive capabilities, but they ALWAYS remain models. It MAY be a more accurate representation, but they are always still models.
As the discriminating capabilities often lag then modelling capabilities, models (replicas) get harder to detect (think of counterfeit bills).