Toby,
Nice to see you building strongly and this particular model. You have done a great job on it, love the weathering, and I can't wait to see your base.
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BTW, you beat me to it.
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I am currently doing a build review of this kit and I hope to have it published here shortly.
While I won't call myself an expert on this vehicle I have researched it rather extensively for the review. Several sources suggest that two versions of this vehicle existed, an early and a late (or “Marianas Model”) version. The vehicle in this kit represents a modified early version. The older vehicles without a bow machine gun were brought up to the newer versions standard in stages. Not all the modifications were done at one time so it is feasible that this kit's vehicle is as I noted, modified.
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My sources are many and varied but I also used the Squadron/Signal Publications, Armor Number 31, by Jim Mesko, “AMTRACS in Action”,1993.
One last point for anyone that might build this kit before the review is out. Part A2 that goes on the left sponsoon, in the instructions does not have a clear positioning arrow. There are no locating features (holes, tabs or anything like that) to help position it correctly. The flat left edge of it should be closer to the first return roller and line up with the first vertical rib on the sponsoon.
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Cheers,
Jan