Depending on the condition of the covers and the collectability you should always keep or find a place for your covers even if you don’t use them. If the cover is broken or damaged upon repair than I would suggest looking for a replacement, either an original or an aftermarket product. Make sure you check the dimensions and pole spacing as many after market products can be metric and not alien up with your current pole spacing. If you have an old “Patent Applied For” humbucker cover, I would not change it in any way as they are quite valuable. Some pickups are epoxied and the covers are difficult to remove and at times impossible.