Relining the barrel will make it safe provided the barrel isn't scrap metal to begin with. Relining won't hurt the value unless it's a very fine and collectable piece and may actually add value. Personally I would be more concerned about the condition of the lock, stock and furniture than I would the bore. Should you buy one and have questions about the barrel send it to Bobby Hoyt. He won't work on it if he feels it will be unsafe after but he also works miracles. He has saved a percussion fowler barrel some one tried to make a lamp of and was in terrible condition besides and he did a damascus double that was pitted to the point of being completely unsafe. I have 3 Springfield barrels that he did and he had to lengthen 2 of them.
"good original 1861 Springfield shooter" It depends on what you are going to do with it. There are a lot of 61 barrels out there that are pitted and are still very good shooters for fun shooting and hunting. You might not want one of them if you were a serious competitor though. I shot an original 61 for several years that had some significant pitting here and there in the bore and did very well with it and with no issues.
