After watching this interview with Deborah Nadoolman Landis, the costume designer for Raiders of the Lost Ark, sparked a nagging question in my mind.
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And that was, is it possible that Deborah may have mixed up her recollections about the fact that the Raider’s jackets had D rings, (D for Deborah) as she stated in the interview when there is a clear image of screen jackets having a rectangular buckle?

The idea that the Raider’s jackets have a rectangular buckle is not news. But what was interesting is the fact that she was very specific about the type of buckle used in the other movies in the franchise as having “two teeth.” Having personally seeing the Noel Howard jacket when I visited London, made me wonder if the Raider’s jacket might have used this same style of buckle?

Over the last few years I have been cultivating a relationship with the curators of the National Museum of American History in the to hope that together we might solve some of the remaining riddles of the Indiana Jones jacket from Raiders of the Lost Ark. With the help of a very like minded curator, contact was made with the Lucas Museum of Narrative Art. He was able to follow up with two questions I had regarding the type of buckle used on the side strap as well as the type of lining used on the original jackets from Raiders.
Here is a comparison image of the buckle from a screen used Raider’s jacket

when compared to the D rings of a screen used Last Crusade Jacket.

We now have further proof positive (which has been mentioned by folks like Brandon Alinger from the Prop Store) that jackets from Raiders of the Lost Ark do in fact have rectangular buckles. Also,it is important to note is that the lining on all four Indy jackets and especially the the Raiders jacket used a poly-blend of fabric for the inner lining and not cotton as previously stated by Peter and theorized by some as such.
Deborah’s fabric sample book which she donated to the Smithsonian even has a lining sample and it’s not cotton.

Though, Peter never took credit for making the jackets for Temple of Doom, the jackets from Temple of Doom used the same materials of the Raider’s jacket in terms of lining and side strap buckle. The notion of that these jackets were made by a French company which has been floated around is because the buckle used had a French country of manufacture stamp.
These rectangular buckles are generic men’s trouser waist tab adjusters and the same style of buckle was made in France, Germany, and Britain.

My father while cleaning out some of my grandfather’s belongs came across his sewing kit and it had a collection of these buckles which both my father and I recall him wearing since all my grandfather’s clothes were tailored for him. The buckle on the Raider’s jacket has a British country of origin stamped on it incidentally.
In conclusion, this style of buckle is not exclusive to the jackets from Temple of Doom but seem to be a design element that was carried over from the Raider’s of the Lost Ark. The notion is that the lining is cotton is wrong too. When you consider that Temple is set before Raider’s it nice to see this carry over.
Getting an answer to what seemed like a simple question took me down a very long and twisted rabbit hole, and I am just glad I was able to reach the end of the tunnel and hope you enjoyed the journey.
Best wishes,
Stefan