One has the flat knurled safety slide and the other has the raised safety slide with crossways grooves.
A bit of a difference in the floral pattern on the bottom of the frame. While these two, and my No. 1 28-gauge also, has the floral pattern on the bottom of the frame extending forward from the trigger plate, years ago I had a 12-gauge No. 1E that the floral pattern extended back towards the trigger plate from the knuckle.
The 28-gauge has the 1935-style Baker J-spring snap-on/off forearm while the .410-bore has the original short Deeley latch forearm. My .410-bore Field Grade from early 1935 has the short Deeley latch forearm while my late 1935 No. 1 28-gauge has the longer Baker J-spring forearm, but mine has the black tip inlay.
459536 05.JPG
My 28-gauge also has the 1935-style stock with the thicker grip and larger checkering pattern --
459536 01 NID No. 1 28-gauge.jpg
and no cocking indicators.
Workers putting parts together to get product out the door!! And, to give us something to talk about!!