It's hard to give you an exact model number without knowing more about it. If it is stainless steel, the model number will start with a 7, example - 744VH6. If it's blue, the 7 is not used. Most of their 44s had a ventilated rib on top of the barrel - that's what the V is for in the model number. If the barrel also had a hunk of steel underneath it running all the way to the muzzle, it was called a Heavy barrel - that's what the H is for in the model number. So, in the above example (744VH6) it would be a stainless steel 44 magnum with a Vent Heavy 6" barrel.
The Monson, Mass. guns are excellent quality. I'm sure you'll be happy with it.
Wayne