In older transformers like the 75T3H, there was a design condition where the terminals were correctly stamped with identification numbers. However, once lugs were installed, the stamped numbers were often obscured by the lug body.
These transformers are typically sold as-is, used, and with the lugs still attached.
To view the terminal numbers, customers simply need to loosen the nut and bolt securing the lug to the terminal, then gently shift the lug left or right to reveal the stamped number underneath.