The DX models will have the nicest externals and trades and maybe some extra parts also often they get a unique serial number.
DX SCAR was in a case with 2 barrels.
DX EGLM came with all the extra magwells and spare parts.
The DX versions are usually part of the first release. Once they're sold out and the production has been going for a while they might not be re-released.
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