Depending exactly where about you are in world 8
Towns I have found with this item are: -FoM- Babylon and Corleone Family - hat
Bat Country and Crater Lake - shoes
Dell River and Forgotten Valley - Clothing
Happy Saloon 2 and Ramoth-Gilead - necklace
Mustang can be bought from any built general store.
And these are just random towns I checked.
http://www.weststats.com
Towns> Town Listing. This gives a list of every town there and how many each town holds. If the items are round about 100 then the town should be a fully built one.