5508 Caseback vs Serial number

[dpa94114]

I've searched the archives - couldn't find anything - so apologies in advance if i've missed a thread.

I have been looking at birth year watches (1961) and inevitably end up at the beautiful old subs...esp the 5508.

What is rather odd is that i seem to keep finding them with casebacks dating to 1958 but serial numbers that run anywhere from 1958 to 1962. These are not shabby dealers, franken looking rolexes.

I know the documentation on the dials from them is anything but set in stone, so I was just wondering if there was some agreement to disagree of sorts - that they produced a boatload of casebacks in 1958 that were used beyond the case production...or bad cases that needed to be repaired...

or something i just do not know in terms of the history.

thanks

doug