The 604 is your Firenze Radiomir, right? -- altogether different than a 372. Regardless, if you have a 372 twin Panerai and the lugs are different than those of the 673, that is interesting. I had always assumed that a 1950 Luminor case was a 1950 Luminor case, whether it's a 372, 673, or something else. I guess there are minor differences between otherwise very similar PAMs.