Pitch is correct about Barling doing the silver work for BBB. Sometime in the later 1880's BBB developed their own smithy and started doing their own silver work.
A BBB from this period is no slouch. At the time, BBB was at the pinnacle of the British pipe trade. BBB was literally Britain's Best Briars. BBB pipes with Barling sterling are a hot collectible, so don't feel sad, be glad! Fix it up and it will be worth the money.
If the pipe has "BBB Own Make" stamped on it, it was made completely in BBB's own factory. Otherwise, the bowl was turned in France and finished at BBB. BTW, the pipe industry at that time considered the French made bowls the superior product, so being French made isn't a minus, except to dumbshit less knowledgeable collectors.
As for when Barling began completely making their own bowls, I don't have an answer. Al Pascia says that they began working in briar in 1865, and I have no idea what their source is for that, and I have a beautiful French turned magnum from 1872. "Barling's Make" stamps existed in the 1890's, so we can date their turning their own bowls at least that early if not earlier. And, of course, in response to the 1906 St Claude carvers' strike, Barling discontinued importing bowls and made everything in-house afterwards.