The number(s) to the right of the bbl date code are an assembly code,,the final assembler of the rifle.

To the left of the bbl date code would be any repair date codes,,same code system of letters followed by a:
'3' for a Repaired and Returned'
'2' denotes a Parts Dept ordered bbl (Kind of like the P in a Circle proof Winchester used for bbls sent out from the Parts Dept.
'4' shows that the firearm was Returned as Received w/No Work Done.
'5' is for a Remington Employee sales
'6' denotes a Canadian order and shipment

Mostly you will see the '3' (Repair) which can be anything from a major overhaul, refinish or just a simple small part replacement or adjustment.
Sometimes several Repair (3) date codes are stamped and they extend towards the muzzle. The farthest one out is the latest one.
The one closest to the rec'vr is the bbl date code of mfg

Not often do you see these other codes (other than 3) stamped but they do show up occasionally.