I assume that by "M1 Pro", you mean a computer with a M1 Pro or M1 Max chip – such as a 14" or 16" MacBook Pro with a M1 Pro or M1 Max chip. All of the Macs with plain M1 chips had 8 or 16 GB of RAM, so if this one has 32 GB, then it couldn't possibly be a 13" M1 MacBook Pro (a machine similar to a 13" M1 MacBook Air in many ways).
A 14" or 16" MacBook Pro with a M1 Pro chip would have a few chassis upgrades relative to a M4 MacBook Air:
- Mini-LED backlist display (with higher PPI and support for playing prerecorded HDR video content)
- Third USB-C (Thunderbolt) port
- HDMI port
- SDXC card slot
That said, my inclination would be to steer clear of the M1 Pro MacBook Pro.
- The processor is several generations old
- This likely would be a used machine from some third party, with no Apple warranty, and maybe no warranty from the private seller either.
Unless the Mac was prepared properly for resale, you could be buying a Mac which you could never set up properly as your own – which might even turn into an Activation-Locked "brick" following purchase.
What to do before you sell, give away, trade in, or recycle your Mac - Apple Support
You could take a look at MacBook Pros with 'Pro' and 'Max' chips available in the Certified Refurbished area of the online Apple Store. I suspect that ones with 32 GB of RAM won't be as attractively priced as the one that you saw, but Certified Refurbished machines from Apple come with a full one-year warranty.
