I had to reuse an old main bearing because I didn't have one in the set I bought that fit with the tang in the proper location. I've read that this type of thing had happened before in here. Sealed Power 4418M010 bearings
I would try to make the tang on the new bearing and just file off the one that's not in the correct position. The worst that can happen is you will need to buy a new bearing. I would modify a punch so that it's the same width as the tang, put the bearing in the block and carefully tap it in.
The tang is not required.. just remove it and line the bearings up when you do your install. Once you have removed the tag, take machinist layout fluid and blue the back of the bearing in that area.. then run a file across it to insure that the tang is completely removed. JW