Definitely leave them the way they are and add sashing. I believe it is important to honor the original piecer. I bought some Dresden plate blocks once and none were the same size. I just added sashing, restitched some pieces that were loose, hand quilted it and won a Best of Show ribbon at the county fair. (I did not enter it, a friend did, and told me later.)
It will mean much more to family members if used 'as is'.