I think this grading problem has been a real albatros on Baker guns all these years. A Parker Bros. GH-Grade was essentially the same in 1888 and 1942, whereas it seems every peice of Baker paper I pick up has things slightly different.
The only Bakers I've seen with obvious grade stamps are the later Folsom made guns. I'm sure many of you have looked at more then I have.
My take on this Baker grades business is that early on there was the B-Grade with twist barrels, the A-Grade with Damascus barrels, and the Paragon Grade with finer Damascus barrels and a bit nicer engraving, profiling and wood. Then, about 1897 they added the Baker $100 Pigeon Gun which was essentially a Paragon but with Pigeons in the engraving and steel barrels. A bit later the Damascus barreled Paragon was also called the P-Grade and there was an N-Grade that was a Paragon with Krupp steel barrels. Then they added an L-Grade Trap Gun which was somewhat fancier. I think that during this time frame Baker also built some fancier guns that weren't shown in any of the paper I've seen. Later over a period of time it seems the R- and S-grades were phased in as the A- and B-grades were phased out. Eventually Expert and DeLuxe grades were added to the line. Then the Paragon Model Nineteen Nine with different shaped lock plates and different bolting.
I never thought of it when I was doing my research on other old doubles there, but I wonder if The Library of Congress has any volumes of "The Baker Gunner." At the prices single issues go for on ebay, and how seldom they appear, assembling a complete set would be quite a task.
Rev, here are some pics of a later Folsom 16-gauge, 30-inch Black Beauty Special Ejector --