Date of mfg help please

[Dalbishop]

Hello Gang,
With all the Remington wisdom out there, I'm wondering if anyone here can help me. I'm trying to discern the year, or at least the year range, of my 870 12 ga. I know the barrel was made in April of 1998, per the 'CS' date code, but I'm trying to get an approximate date for the receiver, as I'm pretty sure the barrel has been changed. I'm hoping that one of you with a keen eye can detect details that might be tattle tales, including the serial # (C173663M) or the art on the receiver. I know that the 'M' suffix in the serial# designates 3", but that's about as far as I can go. I appreciate any info you may be willing to share.

I've been refreshing it, including cold bluing the receiver and magazine, sanding and refinishing the furniture [BLO (5 coats) and Tru Oil (4 coats) with 0000 steel wool between coats], and adding a Limbsaver butt pad. I really like how this thing feels in my hands, the sounds of the action and the overall look. At my next opportunity I will be putting some down range. Thanks again for any help you guys or gals may be able to offer.

David