The bar tools were made by Lassman & Co. in London. They bought the paperweight heads from George Dunlop who used the Pirelli label. Lassman family lore is that the paperweight handles were made in Italy, but that may have been because of the Pirelli name. It is possible that Dunlop also distributed the finished product, but I know of no labeled examples.
See my web page on the subject:http://paperweights.com/lassman.htm
There are claims that assembly was also done at Vasart or Strathearn. In my correspondence with them, the Lassman family was quite firm in stating that that they did not sell the metal parts to anyone, but may have sold completed sets and individual finished items to Dunlop.
The exception is the gearshift knob which was not a Lassman product. If you compare examples with the original boxes, you can see that the packaging for the bar tools and the gearshifts if different. The bar tools were all packed in a fabric lined box or in a fitted case. The gearshift knob was packed in a rather plain cardboard box.