Power Steering box date codes

I have a couple of power steering boxes. Both have 2287262 then below that a tag with heat I assume is the date code. One box has 489 the other 611 with possibly a third 1 or its the edge of the tag from the core when they cast it. One came from a 69 Coronet. But not sure it was original to that car. Any ideas on reading date codes?

They seem to use a minimal casting counter

489 - 4/8/69

611 - 6/1/71