OK, When trying to figure out these "movie mysteries" one must approach it in a systematic and logical manner. First the known facts must be determined.
Raven Bar
1. The screen shots show Indy with an Inglis in the Raven Bar.
2. The book shows a FN as the Raven Bar Hi-Power.
3. It has been stated that 2 Hi-Powers were available for use when filming the Raven Bar. One for blocking and one for filming.
Conclusion - There were 2 Hi-Powers, an Inglis and a FN, during filming of the Raven Bar scene.
Bantu Wind
1. Screen shots show Indy with an Inglis.
2. The Bantu Wind scenes were filmed on a different continent than the Raven Bar scene.
3. The Inglis used in the Bantu Wind would have been rented from a different company than the one used in the Raven Bar. Guns were props and did not travel with the filming crew from place to place especially if they were crossing international borders. They would be rented from local sources.
Conclusion - The Bantu Wind Inglis is a different Inglis than the one used in the Raven Bar.
Overall Conclusion - There where actually 3 different Hi-Powers available for use in the filming of ROTLA. A FN and an Inglis for Raven Bar and another Inglis for Bantu Wind. The title of this thread should actually be "The Case for Three Hi Powers"!!
Now to the discussion of the longer barrel that seems to be seen on the Bantu Wind gun.
1. There were no "long barrel" versions commonly made.
2. The gun may be out of battery as these prop guns did have weaker springs to accommodate the firing of blanks. However if you look closely, the slide is still lined up correctly with the frame and, if the gun was out of battery, you would see the slide sitting a bit further back on the frame exposing the tip of the barrel. Thus I do not think it's out of battery.
3. We have already determined from the analysis above that the Raven and Bantu Inglis where two different guns. It is expected that these two guns, even though being both Inglis's, could have had minor variations.
4. The longer barrel we seem to see on the Bantu Inglis may just be a shadow or perhaps this particular gun being a movie prop may have had a barrel designed to mount a silencer. These type of barrels are usually threaded on the inside and will have a short insert screwed into them when not mounted with a silencer. This insert could be the protrusion we see.
Conclusion - The point here is actually moot. The Bantu Inglis and the Raven Inglis could not have been the same gun as they would have come from two different rental sources. The fact that we may be seeing a physical difference between the two would and could be expected. Until we get the Hi-Def DVD and can do screen grabs to see if the barrel is actually longer or if its just a shadow, we cannot come to a definate answer to what we see as a longer barrel.
Finally you show the picture of a rare Hi-Power with the Inglis indent and the FN rear sight. There is no reason to believe that such an oddity would have been used on any of the sets. The facts presented above already lead us to the conclusion that an "odd" Hi-Power is not part of the equation.
So again to restate the overall conclusion the title of this thread should actually be "The Case for Three Hi Powers" because the facts show that there were at least three different Hi-Powers used in the filming of ROTLA.
Thanks again!