yes
I just tried playing with this in Excel 2008.

Go to excel: preferences: calculations and there will be a checkbox with 'use the 1904 date system'. If your 2 sheets are different it will chance the dates when u cut and paste.

I got around this by cutting my data to a new spreadsheet and copying it all. then changing the preference to 'use the 1904 date system' to match the 2nd sheet i need to copy the data to. Then you do 'paste special' (u bring up this menu using alt-right click on the mac or in edit menu also).

in here select paste as 'unicode text'. this will give u your data unchanged but with the correct date mode. u can then copy and paste it across to your 2nd excel sheet without problem.