Metz only had 3-digit flash models (180, 182, 185) back in the 1960s; Metz later changed to the model number in which the number is the Metric Guide Number, like Metz 32 = GN32 metric, Metz 45 = GN45 metric.
If the flash has not been used, the power storage capacitor may not be able to be charged up by the high Voltage charge circuit, and the ready light never turns On as a result.
A photo of an old model 180 shows that it has no photosensor, so would be a manual power only (probably only full power), as Agx mentions. You would have to use Guide Number arithmetic to calculate what f/stop to use on the lens, based upon the flash-to-subject distance, per the calculator dial on the back of the flash.
https://www.etsy.com/listing/818917...eHbZ4FRDEAqz9c0zHNZcDpi-dA-jJ7aRoCkWIQAvD_BwE