I found "MIP_4coltmp2_HI.dds" (1024x1024) in "pc\sds_en\fmv\fmv1511.sds".

So, I replace "MIP_4coltmp2_LO.dds" (256x256) in "pc\sds\weapons.sds" to HD textures.

.38 Revolver texture in movie scene of Chapter 5 "The Buzzsaw" also changed.