Replacement latch

Hi, Just purchased this home. Sliding glass door is missing the twist knob for the latch and its cover plate (as pictured). Could not find any stickers or marking to identify the the door manufacturer. Can you help identification and parts needed for the repair? Regards

Thanks so much Bob. It took a few more hours reseach that day but I did figure it out to be Andersen. I have ordered a thumb latch.