We don't want to make a kateigor into a saneigor.

Strangely the Gemara first attempt is implying that shtar content is irrelevant paper is paper, Kraft is Klaf (when we know contents, form are integral, and have different legal requirements, whether it's a shtar mamon, get shicrut, etc..)

Now they ultimately answer that money is identical (even today mint dates, different denominations..or even serial numbers isn't noticeable enough).

However we know "Bpanai Nichtav boanai nechtam" if the father is mekadesh his daughter ketanah it has to be infront of two Eidim. So if he gave money infront of to eidim for the purpose of geirushin should be a good severance ergo a gezeiras hakasuv by geirushin which is probably why Rav offers "V'kasav la" but there's no question the teiretz of 10 Shekalim of gold are non distinguishable.She can bring eidim that witnessed her receive a payment that might even be equivalent to her kesubah payments. Kesef by definition are material items with Value that are transferable. Tabbas Zu that's Keseph! So that teiretz of imprints appears to be fine, And Ravs "Vkasav Lah" is an alternative answer...not a necessary one (though my u derstanding is that identical print isn't an answer for two reasons. He was mekadesh with 50 USD in quarters, and is megaresh with a fifty dollar bill & Witnesses are present to state the purpose of the money was divorce.

Avrahom Kevelson, United States