I thought Megumi said there was only 1 finger left on the outside, because Sukuna had 19 fingers. Megumi might not have realized that he spat out 3 of them. I think only the part of Sukuna that was in Megumi's flesh was torn off, but the 3 fingers weren't there.

The fingers in 267 look exactly like when he spat them out in 263, and they also resemble when he concentrated all of his fingers that were in Yuji to take over Megumi's body. Also, the fingers shouldn't be destructible. And Gege making him spit them out just to destroy them later would be pointless