Yes it is! The Early 2017 is the same as the Early 2015 models. Apple only upgraded the CPU chip. Here’s the IFIXIT guide to upgrade your SSD [guide|38535] as far as the SSD you’re limited to Apple’s units, OWC or Transcend both of which make the needed custom SSD drive.
Here’s a good reference: [https://beetstech.com/blog/apple-proprietary-ssd-ultimate-guide-to-specs-and-upgrades|The Ultimate Guide to Apple’s Proprietary SSDs]
* OWC [https://eshop.macsales.com/shop/ssd/owc/macbook-air/2013-2014-2015|Aura Pro X]
* Transcend [https://us.transcend-info.com/Products/No-956|JetDrive 850]