GPT-3 is a model architecture, not a model. While the largest GPT-3 model is 175B, that very paper has a table that includes "GPT-3 XL" (1.3B) and "GPT-3 2.7B" as models in the GPT-3 architecture. The 2.7B model is the same size as Ada, a model that OpenAI currently sells API access to under the moniker "GPT-3"
None of the other models are even close to the big one, and the paper also suggests calling the big one "GPT-3". And people do that very often in practice. So it's often ambiguous but saying the term only means the architecture isn't right either.
