Most warbirds don't have any lights at all, right?
Incorrect. Most American aircraft (at least) had some sort of Nav/recognition lights on the wings, Landing Lights and Formation lights. However, None that i have seen ever had strobe lights (pulsing white lights), which is why when i said if they had them, it had to have been done by the private owner.
This got me curious about specifics on WWII aircraft, so i did a little searching on the net to see about aircraft other than the P-47, P-51, P-39, B-25, B-17, T-6, A-20H which i have all been arround or have looked through the photo logs of our previous aircraft.
this site seemed to have a good bit of knowledge on the subject. I found it quite interesting and it backed up my above statement
http://www.ww2aircraft.net/forum/aviation/recognitiion-lights-11908.html