Knowing more information might save some hastle..
If you know the load data, (loaded them yourself), and it's not even near the warm side of things, or where you'd start if you were working a load up, If they're loaded to spec dimmensions, If they'll chamber in the gun you want to shoot them in, you might just do that.
Would I do this with the loads that I've got the bullets seated out just shy of the lands in my Ott-6, and shoot them in my nephews gun of different manufacture? No.
But, I have swaped rounds that were 'neck sized only' loaded to spec lengths between 30-06 rifles. Done the same with .243 rifles/ammo with no affect at all.
There are enough differences in retail ammo case thicknesses that affect more. Will these neck sized rounds be as accurate when fired from a different chamber/barrel than what they were worked-up/fire formed in? Hard to say, but to me it's not worth the hastle of resizing the cartridge as long as it will chamber safely in the rifle you intend to shoot.
If they are suspect 'warm loads' or you didn't create them yourself, then pull the bullets. Dump the powder, and resize/reload, starting from scratch.
-Steve