Can you identify this item?

It's a silicon chip

It is a very old Texas Instruments microchip used in the guidance systems of US Navy Polaris missiles.

I don't usually do this, but I found it interesting.

From Wiki:

The TMS1000 is a family of microcontrollers introduced by Texas Instruments in 1974. It combined a 4-bit central processor unit, read-only memory, read/write memory, and input/output lines as a complete "computer on a chip". It was intended for embedded systems in automobiles, appliances, games, and measurement instruments.

It's an obsolete ROM chip.