Here is a shorter discussion:
https://orcuttfamilyhistory.wordpress.com/william-orcutt-mary-marth...
Both this and the wikitree discussion lead me to think the birth date should be the 1639 one, as that seems most plausible, based on these excerpts:
"It is unlikely that William Orchar or any other man baptized in 1618 would have been William Orcutt of Bridgewater. William Orcutt's children were born during 1664-85. This suggests that it is most probably that their father was born sometime in 1633-1643. Thus William Orchar was born 15-25 years before William Orcutt's expected date of birth. William Orchar/Orcutt's advanced age (of about 45) at the time he married Martha/Mary Lane in 1663 could possibly be explained by his having previously been married, no reliable evidence has been found to suggest that that was the case. "
Newer, More Plausible Theory: William Alcocke of Mancetter
"With the benefit of modern online digital databases, in 2000, Joel Thomas Orcutt discovered a more plausible baptismal record for William Orcutt of Bridgewater: the record for the baptism of a William Alcocke in Mancetter, Warwickshire on October 20, 1639."
"The 1639 baptismal date for William Alcocke is very consistent with the fact that William Orcott's children were born in 1664-85 and Martha/Mary Lane's estimated date of birth in 1640-6.
No record of William Alcocke of Mancetter has been found in England after his baptism, which is consistent with him emigrating to New England. "
I would suggest we change the date of birth (and/or baptism) on this profile to October 20, 1639, with a note in the Overview section referring to these links.