1) Yep this type latch is generally attached via the rivets and some times with a piped upper edge that goes through a "tunnel" in the edge of the metal latch. Weight of the leather is most likely in the 3 zo range.

3) I'd bet the black stain is most likely vinegar black - iron or steel dissolved in vinegar - it is technically a reagent that reacts with the tannins in the leather to stain it black. Since it is not a dye there is no rub off. The finish is hard to say due to the fact it may have various type finishes put on it over the years, but a mix of tallow and beeswax and sometimes a bit of rosin is not an uncommon period finish.

That type latch is common on Scottish sporrans so that may be one source - some of medieval and later sutlers who specialize in that type goods. Ohio Bag company may carry them. And you may also find a cheap sporran or old purse with such a latch on ebay.
Then again here's a guy making one out of brass.
http://www.thescotsforum.com/s...ct-(long-term)/page5

Thanks, Grey Wolf--great information and link!

CSK