Winchester never built a rifle with a hexagonal barrel.
Hexagons have SIX sides.
If you mean the OCTAGONAL barrel (with 8 sides), they were made until 1935. Google "1894 Winchester".
Some good photos would really help a lot, as would knowing the length of the barrel and the serial number range.
There was a whole barrelfull of custom features available for this rifle, some of them very rare and worth a ton of money.
I once saw a .38-55 Carbine with SEVEN special-order features. There might have been half a dozen made like that one. OTOH, my own has half a million clones.
Folks here will be happy to help, but they have to have something to go by.