Personally I would only worry if this involved an hotel you have never previously booked or stayed at

Hotel staff re-enter the details passed on from Hilton into their individual hotel system , whether Opera or one of the usual other offerings. If new booking matches a surname already historically in their system for one reason or another bookings sometimes get assigned to a matching surname

Regards CC questioning with an hotel, you could have simply asked hotel to confirm if Last 4digits matched nnnn which is a simple yes/no answer, hotel correctly should not tell you the actual digits