The "15 41" is the tooth count of the pinion gear & ring gear, respectively. Divide 41 by 15 & you get 2.73. The "3 82" means it was made in March of 1982.
Look inside the open part of the carrier & see if you see a rod about 5/8" in diameter & 4 intermeshed gears. If that's all you see, it's not posi. If you see 4 or 5 coil springs or an S-shaped flat spring between the two side gears, it's posi. If you see the picture below, it's a Gov-Lock, which is not so good.
