Dating 870 Classic Trap - bad barrel code

[yo1dog]

Looks like I have a miss-stamped barrel code on my 870 Wingmaster Classic Trap. This is the only marking on the barrel. Is there any other way to date these?

Purchased new from big box store sometime between late 2013 and early 2015.

Serial: RS35473T
Barrel Code: ??

I do have the original box and manual.