You can get that type of nametag anywhere. If you are in the Baltimore area try F and F Jacobs on Wicomico St. Be sure and call beforehand.
If you want the same thing that FDNY uses call Headquarters FDNY and talk to someone who handles uniforms. They have a store where you go to get the merchandise. Or get on the internet and search for Horace Small Uniform Company in Nashville Tenn. They have the contract for FDNY. Call them.
I was in the uniform business for 35 years selling fire and rescue so this is reliable info.If this does not help I would try and get a phone number for the UFA in NYC
(IAFF) they could help.