Figured this knife needed its own thread. There is already some great info about it, but it is often buried at the end of other threads labeled with Gerber and Night Raider titles.
A brief "highlight" list of must-read threads regarding Hudson's knife (and by default this knife) are these 2 threads:
viewtopic.php?f=7&t=12598&hilit=gerber+chart-This thread highlights the various types and styles of Gerber that have been produced through the years. In this thread I suggest to get a "screen accurate" gerber (correct Tooth-per inch, correct style sheath, correct handle color, and correct blade) one needed to find a 1977-79 era knife and blue the blade. Bluing the blade was actually quite common as they came with "field bluing" kits when sold new. It made so much sense...for a little while. That theory would prove short-lived!
viewtopic.php?f=3&t=13654&hilit=gerber+chart-This thread started out focused on the modern day series of "Raider" knives as 'fill in' items, but quickly blew up everything we thought we knew about Hudson's "Gerber". Specifically screen grabs were used from the "knife trick" scene to show it wasn't a gerber at all. The hand guard was not that of a real gerber (angular contours, flat faces) and was actually that of a clone (rounded contours which tapered to a point). The MM-IV was targeted.
http://militarycarryknives.com/CopiesClones.htm-This page highlights the various "clones" of Gerber Mk2s and there you find the candidates for Hudson's 'true' knife. I think it goes without saying the Explorer MM-IV is the top suspect. The other clones have the wrong sheath, wrong # of teeth in the serrated area, or the wrong blade material (A shiny 440 stainless blade cannot be easily darkened as it appears in the film. It is an elaborate process and only the MM-IV had a factory applied black oxide finish).
In fact, the Explorer MM-IV aces the test in every regard:
-Correct handle color and features (as screen matched in the 2nd link)
-Correct blade features which matched the screen cap'd blade (TPI, wasp, darkened blade)
-And now as these pics will show, an
even more accurate Sheath than a Gerber.
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In the screen grabs of the sheath you see "straight" side walls, not curved inward mimicking the 'wasp' of the blade like on the Gerber.
You also see a perfect match for the retaining flap/tab. The taper has already started to a point by the time the tab reaches the metal 'button' on the MM-IV, unlike the gerber which has a less subtle taper that starts after the button. Also the button sits very close to the edge of the opening on Hudson's/MM-IV sheath as opposed to further down on the Gerber sheath.
I am not saying all Gerbers need to be removed from costumes. Far from it. They are still great "close enough" items

It is fair and logical to say the Explorer played the character of a Gerber even, so do what you have been doing! I just want to slap this nail in the topic.
Also, even though they don't necessarily prove anything knew, I took these pics of the MM-IV side by side with a 1979 gerber, so figured I'd post em.
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It is interesting to me the MM-IV is just a tiny bit bigger. Felt heavier too.
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The higher start to the serrations also matches the screen caps.
Fun stuff.