how to find part number of 2017 imac

There is a path that could take you there, includes other detailed info.

• Identify your iMac model - Apple Support

https://support.apple.com/en-us/HT201634

From within this article are 4 product names & dates; follow breadcrumbs.

[Without proper identifiers, I see a definite lapse between here and there.]

2017:

iMac Pro

Model Identifier: iMacPro1,1

Part Numbers: MQ2Y2xx/A, MHLV3xx/A

Tech Specs: iMac Pro (2017)

User Guide: iMac Pro (2017)

iMac (Retina 5K, 27-inch, 2017)

Model Identifier: iMac18,3

Part Numbers: MNE92xx/A, MNEA2xx/A, MNED2xx/A

Tech Specs: iMac (Retina 5K, 27-inch, 2017)

User Guide: iMac (Retina 5K, 27-inch, 2017)

iMac (Retina 4K, 21.5-inch, 2017)

Model Identifier: iMac18,2

Part Numbers: MNDY2xx/A, MNE02xx/A

Tech Specs: iMac (Retina 4K, 21.5-inch, 2017)

User Guide: iMac (Retina 4K, 21.5-inch, 2017)

iMac (21.5-inch, 2017)

Model Identifier: iMac18,1

Part Numbers: MMQA2xx/A, MHK03xx/A

Tech Specs: iMac (21.5-inch, 2017)

User Guide: iMac (21.5-inch, 2017)

Usually more than one model number ~ will be found in the range of date.

• Ultimate Mac Lookup by Specs: SN, Order, Model & EMC Number, Model ID @ EveryMac

https://everymac.com/ultimate-mac-lookup/

I get them from MacTarcker.

iAlmost posted download link to get MacTracker's database:

https://mactracker.ca/

Sometimes these work better as filler, with other sites.

When you've got several choices, hard to choose one.

Could the part number be on the bottom of the iMac foot, along with the serial number?