Can I make a re-entry permit at Suvarnabhumi Airport when departing Thailand?

Departure 2 sells the re-entry permits.

Check with the staff at bottom of escalator as only one side has the reentry

After you’ve checked into your flight and gone through the security line (where security officers check your airline ticket and scan your carry-on luggage) but before you go through immigration and get stamped out of Thailand, there is a small kiosk or desk area that you can apply for a re-entry permit.

The re-entry permit desk at an international airport is open every day the airport services an international flight. If you have an international flight departing at 12pm noon, 9pm, or 2am, the office will be open.

yes.