Gun Parts Corporation has many parts still shown as available for it, including barrels and bolts (two of the parts that sell-out the quickest, in my experience). No hammers, though. Click link to see list of Noble models and select the appropriate one to see a parts list (note there are a handful of M275 sub-models; this could mean major differences in parts, finishes, or other items, so have him check the EXACT model number from the barrel or receiver before ordering):
The schematic seems to show a slide-action, or at least, a non-traditional style of lever-action. Does it look like a Winchester-style lever-gun, or is it different in one or more ways?