OK - but even if you find one or two suspect examples, it is no hard evidence. Both VMS foliator and Kelley may have had moments of bad mood when their pens just went astray. I was still taught to write with pen and ink (early 1960's) and can remember that when the pen ran out of ink, you dipped it in ink and continued the letter from wherever you finished.
Before you do that, perhaps you could check both against a neutral witness - some sample English manuscript in the British Library from circa 1580-1600 with foliation which was certainly *not* by Dee or Kelley. If they look identical again - then it would indeed be a waste of money to buy the reproduction!