Always try to download the most recent build available for that version. While the Android version (7.1) is old, the Google Play Services inside the zip might be updated. However, be aware that Google has largely stopped supporting Play Services on Android 7.1, so finding a build from 2018 or 2019 is common and acceptable for these ROMs.
Google Play Store, Google Play Services, and Google Services Framework. Standard Apps: open-gapps-arm-7.1-micro.zip download