Re: Stevens .410 Model 311-A
AFAIK, the same gun is denoted interchangeably as either the 311 or the 311A, w/o any difference in parts.
.410 values, for just about any SxS, have skyrocketed in the last ten years - waaay outside the normal values attributed to 12 & 16 gauges, and well more than even for most 20ga's also.
The last .410 Stevens 311 that I sold was at a gun show, over eight years ago - and I was paid $450 for it, then.
That was a time, when I saw & bought 20ga 311's everywhere for $200-$250.