Hello...Welcome to the forums.
The set is known as "the red letter set", and celebrates the famous Model 37 Shotgun. Set was made in 1987.
They come in a large black box, stamped on top and a note of authenticity. One bolster on each knife is etched with matching serial numbers.
Each blade is color etched/stamped with the Model 37 shotgun...each with the different gauges available at the time (410, 28, 20, 12, 16)
I have the box which I can take a picture of if you need it...Pics provided are of just the knives.
The set represents the first of the Winchester reproduction knives made...they are hard to find, but they do turn up occasionally.
Below is a "family" shots of some of my Winchesters reproductions...You can see the red letter set at the bottom...as you can see they are very small in comparison.