How can I verify if my Apple dispute case number is legit?

Re: is 102*******89 a legit apple dispute case number

Had issues with gift card scam. Unsure to trust 102*******89 (provided by email.apple.com

You may want to try signing in to your Apple "My Support" webpage:

The status of any support cases can be checked there.

My Support - Official Apple Support

As you feel unsure about the email, you are likely wise to trust those doubts:

Apple provides an address to forward suspicious emails to: reportphishing@apple.com.

If you’re on a Mac, you can select the email and choose Forward As Attachment from the Message menu.

Else: Apple Support have articles online that may be helpful:

About Gift Card Scams - Official Apple Support

and

Recognize and avoid social engineering schemes including phishing messages, phony support calls, and other scams - Apple Support