The #1 shell plate is for common head size of 30.06/308/270/ etc.
The 45 ACP has the same size head as the above cartridges.
I have loaded 45 ACP with the #1 on my LNL and results were just OK. I bought the #45 from Grafs and the results are significantly better. Fewer, hangups, fewer crunched cases, etc.
When I got the #45 I miked it and compared it against the #1. There ARE differences between the two. (I don't remember the specifics). The #45 shell plate holds the 45 ACP much tighter with less "wiggle" room.