Author Steve Sheldon is somewhat correct with his observations:
"During the Civil war, the firm of Schneider and Glassick of Memphis, TN, produced perhaps some 50 copies of the Colt 1851 Navy, though some of the extant copies have brass frames but iron trigger guards and backstraps. And the cylinders were smooth-sided with no naval battle scene engraving and no step-down in diameter towards the rear. There are no reproductions of this revolver available. There are, or were, a few reasonable reproductions of historical brass-framed revolvers made. There have been runs of the Confederate Griswold & Gunnison made by various manufacturers, and likewise Pietta as of today makes a copy of the Spiller and Burr.
So if you want a historically-accurate brass-framed revolver, about your only commercially-available reproduction option today is the Pietta Spiller and Burr. Lodgewood Manufacturing offers a copy of the Griswold & Gunnison from time to time."
The bolded section above is not correct. Pietta markets two brass frame 1851 Navy "type" revolvers: the Griswold & Gunnison .36 (with part round/part octagon barrel and smooth non-engraved cylinder) and an 1851 Navy .36 (with octagon barrel and engraved cylinder). Pietta bought out EMF awhile back, and now EMF is the primary distributor of Pietta products in the US. Since ~2001 Pietta has used CNC machining for all of its revolvers, and the parts interchange very well. If you wish to procure a plain non-engraved cylinder to create a Schneider & Glassick, VTI and Taylor's sell them and you can find "used" ones on Ebay.
I have many Pietta 1851 Navy "type" .36 revolvers and I can attest to that. I like Confederate revolvers and have created several, four of which are below.
Schneider & Glassick and Leech & Rigdon
Griswold & Gunnison and Ridgon & Ansley (12-stop-slot cylinder by me)
Sheldon also refers to Lodgewood as a source for a G&G. Lodgewood specializes in defarbing/antiquing Italian replica revolvers to look like 150+-year-old guns and charges a fairly hefty price to do so.
http://www.lodgewood.com/Confederate-Griswold-Gunnison-Revolver_c_305.html
Regards,
Jim