I have an 87 vert with some #'s on my passenger side and driver side window don't know what they are . They look like if they were sandblasted. Is this from factory? and can somebody tell me the meaning of them

It sounds like security etching a previous owner might have had put on the car. Assists with tracking parts if stolen. This is just a guess as I've never heard of this being applied from the factory.
Do the numbers match anything else on the car, like the VIN?