The 1851 Navy "pattern", that is, with octagonal barrel was only produced in .36 caliber. The 1860 Army was produced using a 1851 frame with the rounded barrel. Basically, if it has the oct. barrel, and is in .44, it is not an accurate repro, from what I understand.
That said, there are some very good looking revolvers on an 1851 pattern. Though I don't own one,(yet), I certainly wouldn't turn one down if it "spoke" to me. One such is the "sheriff's" model sold by cabelas. The polished steel one with the photo engraving. I like it, and may get one (or two), yet.
I don't know if it's that big of a deal really.After all, the main goal is to have fun, have fun, be safe, and have fun.