Signal-Stat Flasher Date Codes

[VetteSpaz]

Good Morning Guys,

Here are some shots of Signal-Stat 170 flashers. They were used on Chevrolet hazard warning flasher units during the mid to late 1960s. My question to the experts here is how to read their stamped date codes? Here's two examples of S 285 and S 056.

If you know for sure please share it with us here. These things have gotten very expensive and I'd like to pre-date my car's build date with one of these originals. My '66 Corvette calls for the 170 flasher.

Thanks for any help,
Mike