1963 Chalk marks

[Deanlow]

Hello everyone
Just looking for some advice regarding chalk marks the factory put on the 63 Impalas. Recently found a factory chalk mark after i removed the lh fender so I can replace the door hinge pins. Can anyone tell me what the numbers mean please? Looks like 1853. Thank you.

 

[Carl 1962]

It is probably 853, which is the trim code for aqua bench seat interior on an Impala. This aligns with your cowl tag in your other post which I decoded previously.