Genuine Barcelona Chair Identification  

Firstly, sorry I know this has been asked before, and have read past posts, but I'm still unsure about this one.

I'm trying to work out if these are genuine or not, they have 17 straps, no visible welds. The chairs were apparently inherited from the seller from her grandmother (I'm in NYC). But the back cushions appear a bit short - they also look slightly different to the bases - possibly just the backs have been replaced at some point? One the of cushions still has a Knoll tag on the bottom. I can't spot any markings on the legs from the (bad) photos, but if you all think they might be genuine - I will take the drive to have a closer look. And any other details to look out for on these when I do?

https://photos.app.goo.gl/ej1JddH2pCd76rsY6