Hey Jim
You are marching along in leaps and bounds!
The work you have done to spiff the bogey housings is great, and the homemade skids really look the part.
There were most likely more of the M4A3(76)W in footage of the push into Germany, but there would definitely be M4A1(76)W also; survivors from Operation Cobra through to latest marks which had muzzle brakes etc. As for the EECs, I reckon they add that extra bit to a beaten up Sherman especially with a few of them randomly absent...
I have seen many photos of the tracks skids caked with mud; so much so that the gap underneath is packed to the gunnels! Don't forget to add some mud to the underside of the sponsons and the fenders
Good stuff
Brad