I sure don't remember anything about a tab lining up. The upper bolts between the engine block and the tranny bell are very hard to reach, and the flex plate bolts are difficult to get to, but still it is not impossible, just plan on more time than it would take with most other makes.
I would drain all the trans fluid before taking the old one out. Most have a drain in the pan and a drain plug in the torque convertor. I did pull a trans out of an 81 300D that had no plug in the pan. Then you have to loosen the pan bolts and let it drain.