Many of the prints do look a lot like 30's feedsack to me. The solids are very reminiscent of that era.
Also, I'm not sure how they did it back then but now days, Trip quilts are diagonal set squares--not on point diamonds. I would think they would have done it the same way back then otherwise you have bias issues to deal with.
As for your newspaper quandary; you would probably have to convince your customer to take it to an appraiser or do it yourself in order to convince them to change their mind.
I am amazed at how well kept these appear to be if they are truly as old as the newspaper & fabric designs appear to indicate. Whoever stored them did it very well and must have kept them in a very clean and almost climate controlled environment--just amazing if they really are from that time period!