870 trap guns are a tangled and complex path to follow. The T grades started off at A then B, C D and F.
A was slightly better wood than standard WMs. The barrels were 28 or 30" and either Full or Modified.
Monte Carlo stocks were an option thorugh the series, and so was a Sun Ray variant with blond wood for a while.
B grade was better wood yet, and along with A grade had the impressed checkering we all know.
C grade upped the wood again, and used cut checkering in several patterns that varied over time.
D had engraving over 50% of the receiver and was a Custom Shop offering.
F had 100% coverage. D and F both had exhibition grade wood and often custom fit stocks.
Besides the T grades, an All American model was offered in the 60s,IIRC, with a gold badge on the receiver like the Classic Trap models sold today.
Letter grades I've seen have ALL had a letter grade suffix after the serial number on the receiver with a V as the last part of the number.
Example,XXXXX V TB.
Forearm length varied from long to extra long and checkering patterns also.
NOTE:
Since 870s are easy to take apart, often parts get swapped. I ran across a Magnum receiver 870 that had a high rib barrel and M/C stock at a reputable shop with a trap grade price on it.
Trap hustlers used to buy both a TB and TC, swap the wood and sell the TC off with the lesser wood at a TC price.
Still, a letter grade 870 of any grade is a fine shotgun and oft a joy to see.
Enjoy.....
