Items for sale now appear on my new website at:
The strap lugs on the 139 are made of brass with a steel insert to stop the soft brass being worn away. Unfortunately, the idea doesn't work that well and the steel inserts move and allow the brass to be worn away. Later cameras, such as the RX, have stainless steel lugs which don't wear.
I once managed to get a small quantity of the stainless steel ones but have now used them all so have had some custom made. These are now available to buy. They fit the 139, 137 and 159. I believe they also fit the RTS and RTSII but this needs confirming.
Please see the new website above for pricing.