That fireplace carried a datestone with an inscription reading "1614 John McNamara and Onora Clanchi bilded theis cheimneis in the year of our Lord", and for a time that was enough to push the building's perceived origins back by a century or more. The house appeared in official records from 1992 and again in 1996 under that earlier date, the stonework lending it an antiquity it may never have genuinely possessed.

The problem is that the fireplace almost certainly did not belong to Ballykilty house at all. It is now considered to have originated at Danganbrack Castle, a separate site, and at some point was relocated and installed in the house, carrying its 1614 date with it like a false identity. The McNamara name on the inscription is a familiar one in Clare history, a Gaelic family of considerable regional power, and their mark on a castle fireplace would not be unusual. But the house itself, stripped of that borrowed antiquity, appears to date from the 18th century. By 2013, the fireplace had been reported missing entirely, severing even the physical link to the misattribution. The records have since been corrected to reflect an 18th or 19th-century date for the building.