Yes John,
Those look like the 317A out of the NGL design stable. the ones we had till 2001 ish for our C130 application, the circular bits on the front were all shiny where the paint or dyed anodising had worn off. We replaced them with the 417A (Jaguar type) as they became available when the Jaguars went out.
I arranged transfer of the 317s to Boscombe for use on their Alpha jets. I think in the end we only had a dozen that passed the bench tests. they had a skilled guy in their 02 bay who could make one good one from three. Oh there were also left hand and right hand versions which further complicated the issue. All you had to do was turn the bottom fitting around and change the stock number. that screwed the stackers computers up!
the masks we adapted were also a nightmare. had we [MoD] been sensible we would have held kits of parts like Lego. (I think this was the case pre 1990s) In the naughties each aircraft type appeared to have a top assembly they bought in. Various companies then gave all the individual parts new numbers. We were then being ripped off for spares. many of the mouldings including the main mask and exoskeleton were made by Camberley Rubber. The development having been completed in house at Farnborough (Pre QQ) yet all these 1st Tier suppliers were claiming IPR over bits they had not designed.