Both 4to and folio read 'see.' Rowe made the obvious correction.
"A mark marvellous well shot; for they both did hit it."
It was the 4th folio that supplied it.
"An if my hand be out, then, belike, your hand is in.—
Then will she get the upshot by cleaving the pin."
'Pin' is the correction of the 2nd folio; both the 4to and 1st folio have is in, as in preceding line, and possibly so the poet wrote it; for it makes a kind of sense, and he may have had his reasons for using it.