This is an EXEXEL sized pipe, though not marked as such, and although other stampings indicate this isn't a "pre-Transition" Barling, the grain indicates that pre-Transition briar was used.

The quote above is taken from the description of a Barling currently being offered on eBay. There is no way from the grain that any assumption should or could be made as far as the source of the briar. Sometimes you'll see claims that the nomenclature. T.V.F. (The Very Finest) indicates briar sourced from the earlier period but this is incorrect.

Barling essentially has two distinct periods of manufacture that are are referred to as Pre (basically 1960 and before and sometimes called Family Era) and Post Transition. Barling's briar is legend and with cause. Through 1954 they owned their own sawmill in Algeria and thus controlled their production from ground to mouth but after 1954 they purchased their briar and at least through 1960 it was exceptional wood. Pre-Transition Barling's command premium prices.

You should buy pipes on what you can determine as fact.