Unless this is a high grade 21 I would not worry about the records. If the fit and finish are up to par, this is either a well made lunch box gun of one more gun which never got recorded. I assume it has a serial number. So buy it for what it is, a great shooter with at worse an interesting past. Since there are not that many 28's to start with I suspect that if this is a lunch box gun it is a one of a kind. And there are no faked 21's out there like there are Model 12's altered into a "rare" 28 gauge gun and being sold for major bucks.
I have bought land and stocks for investment, my guns are not investments they are toys to be shot and enjoyed. If their value keeps going up so much the better. I have three 21's,.all three are two barrel sets, a 12 ,16 and 20. My desire for a 28 or a 28/.410 set gets a little greater about every couple of years but as you mention the prices for the small bores are steep. Too steep for toys when I have so many other needs of other toys. Choices, choices, choices.
