Mortise latch

I'm not sure I understand your question. What two products did you want me to compare for you? When you say 45 and 90, are you talking about degrees, as in the angle of the slot? If so, that's the major difference between them: one lock has a 45 degree slot and the other lock has a 90 degree slot.

If your old lock is broken, then there isn't really a good way you can determine what angle you need. You will have to look at what angle your handle's thumb lever takes when it's in a normal position and use your best judgement.

Thanks for the photos. As mentioned above, I cannot tell you if your original slot was 45 degrees or 90 degrees. I can tell you, however, that the 82-223 will not replace this. You see, the 82-223 has a squared face, while the face on your mortise is rounded. That means it won't snap into the hole as it should.

The 82-218 may be your best option. This has a 45 degree slot, but I have to stress that the orientation of that slot is not something I can confirm. Your best bet is to look at how the thumb lever on your handle works. You should be able to gauge whether or not that fits 90 degrees or 45 degrees by how it operates.