Signed Prints

[kdj]

Hello!
I have a set, 8, of Arthur Singer bird prints. All are mint, in original frames.
While researching possible value, I see a variety of these prints in complete sets or partial, with a big range of prices.
One is around 175.00 complete, "signed".
Here's what is bugging me...
most of the internet postings/ads say the prints are "signed".
It looks to me like the signature is part of the print. If I see a pencil or ink signature, (besides the printed one) I feel that is a true signature. So, if an artist signed his/her work, originally, and it is part of the print, how is that viewed that as "signed" ?
I attached 4 pictures including two of signatures that appear to be hand signed. Those differ from others that look more as part of the print.
Thank you!

[mart]

 You would have to match each signature on the exact same print to see if there are differences in how it was signed !! You can not tell unless the same print is used !! He was commissioned by several magazines to do work so if he was commissioned and paid by the magazine,,he has no copyright !!  And the magazine could make all the copies they wanted to and sell them which may be what they did !!  Would almost have to use a jewelers loupe to determine if they are hand signed or copied !!

[kdj]

Thanks mart!
I have been looking into comparisons and am not done yet.
 

[mart]

I will look and see if I can find anything too !!