<VV> Pressure switch

[J R Read_HML]

I just noticed a code on the bottom side of the metal "ring" area and wonder
what it is.  There are 4 numbers and they nearly line up with the vertical
slots.  3 of the numbers are on one side 3 - 9 - 7.  Across from the 9 is 4.
Is this a run # or date of manufacture?  The one I'm looking at is ACDelco.

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Later, JR
'61 Rampside Standard 4/110
'65 Monza Convertible 4/140
'66 beater Coupe - icemobile 4/140