Yes they are all up to date.
Oddly enough on the configuration instructions for drop date it says this.
“DropDate can store dates as a UNIX timestamp (the default), or in YYYYMMDD format.
The latter is included for use with Solspace’s Super Search module, which doesn’t play nicely with UNIX timestamps for dates prior to 1970.”
So perhaps there is issues with other addons or EE itself not sure, although i had dates before 1970 that worked fine. I dont have supersearch on this site just so there is no confusion there. Dont really want to uninstall structure to see if that is the issue. I’m kinda pressed for time on this site (isn’t that always the way) but perhaps when I am done I will do some testing on a vanilla installation with very old dates and see what happens. Gradually add in my stock addons and see if it is an addon issue. Would be interesting to see if anyone else has had the same issue although I dont imagine its very often people need dates from the 1800’s