Your source is slightly confused. The original design of the Apollo Guidance Computer used core-transistor logic and they built three prototypes 1A, 1B, and 3C

Your source is slightly confused. The original design of the Apollo Guidance Computer used core-transistor logic and they built three prototypes 1A, 1B, and 3C in large racks. In 1962, they switched to integrated circuits and built rack-mounted IC prototypes (AGC3 and AGC4) using Fairchild Micrologic. They built the Block I AGC systems starting in 1963 and launched one on an unmanned flight in 1966. Block II planning started in 1963 with qualification tests in 1966. All crewed flights used Block II systems. Source: "Journey to the Moon" by Eldon Hall, designer of the AGC. TL;DR: the core-transistor logic AGCs were prototypes before Block I; Block I used ICs. You can see a photo of a Block I module with flat-pack ICs here: https://www.computerhistory.org/revolution/digital-logic/12/278/1441 https://www.computerhistory.org/revolution/digital-logic/12/...