A couple of things are useful in evaluating the 
authenticity of AMG cels.  

1.  There are often observable differences in the 
highlights in Belldandy's hair between the video 
frame and the repro.  It seems to be very hard to 
get all of them right.

2.  There is a series of film manga for the OVAs 
(one for each eposode) that appear to accurately 
reflect what is on the screen.  Although they 
only have a fraction the frames, it's possible 
that the ones you're interested in are in there.  
In fact, all three of your cels (including the 
one you sold a week or two ago) were in there.  
And I believe your first cel was also a repro...