I found this on the internet but it doesn't say anything about limited to 500:
Marlin Model 1894 Cowboy II 357 & 44 Mag 10 shot Rifles
Marlin 357 Mag & 44 Mag Cowboy Rifles $745 In Stock!!!!
This handsome rifle, available in 45 Colt, 357 Mag./38 Spl. and 44 Mag./44 Spl., has become the standard by which all cowboy rifles are judged. From its elegant tapered octagon barrel, with deep-cut Ballard-type rifling, to its straight-grip walnut stock and squared finger lever, this rifle is pure Old West. To accommodate tang sight installation, the serial number is located on the left side of the receiver. 45LC version sold out.
Found this on this sight:
1894 Cowboy II: 1996-2000
357 Magnum, 44-40 Win (discontinued 1999), 44 Magnum
24 " tapered octagon barrel, Marbles sights.
Assuming it's in good shape, that's a great price if it's one of these.