are these authentic knoll parallel bar chairs?  

Here are a few more photos.

I don't own this chair but just comparing to detailed photos on 1stdibs listings, they look legit to me. It's hard to imagine a knockoff that is that true to detail that the general population probably doesn't care about.

For future reference, it will be most helpful if you can take photos from the same height as the chair so that it's easier to see the side profile, a true front view, and a true back view. When you are standing, the camera is 4-6' off the floor instead of 2' and the images of the chair end up distorted. IPhones are worse than cameras, I think. More lens distortion.

I don't know that much can be done with splits in vinyl, unfortunately. There are some patching glue-like products but they're not something you'd wanna use on fine furniture. The seats in an old pickup truck--sure! But not so much a Knoll chair.

Thanks for your comments Spanky. Yeah I am really not sure what to do about the tears. I would like to recover them, but I am not sure I should just take them to the local upholsterer, seems like a lot of detail that needs to be accurately replicated. If anyone knows someone in so cal who has experience with these chairs let me know.

cheers

I will probably just enjoy them as is for a while and maybe the old vinyl will grow on me.