Help to find this slidding door parts.

I don't think you'll be able to find this exact handle set anywhere. This is a very old style that hasn't been made in years. 

Your mortise looks pretty standard, though. I'm just not sure if it has a 45 degree slot for the key. You should double check that to confirm. If it does, then I think you can use our 82-030 as a replacement. Just note that the 82-030 has a 3-15/16" hole center spacing. If yours differs, you would need to drill new installation holes.