Sliding Door Part

We have a sliding door that was installed when our house was built in 1977. At the bottom between the doors (only the right door slides) there is a space that allows air, dirt, and insects in. I assume there should be some kind of part that would block this and perhaps be a bumper? I enclosed 2 pictures of the bottom and one of the top between the two doors. Any assistance as to what part(s) we should order would be much appreciated. Thank you.

Looks like a 86-010 guide if that helps any.