Retrofit is a little different than other sections of the Fire Code. You need to read it carefully and enforce only what it says and nothing more. The purpose of retrofit is to upgrade the construction to a higher safety standard with the least amount of work and expenses. 220.127.116.11. doesn’t state anything about a tag. As long as the door functions properly, has a self closing device with existing metal frames you meet the requirement. If you notice it doesn’t even ask for rated frames as long as they are metal. Similarly with the self closing device, it doesn’t need to be rated if existing as long as there is one there.
You don’t need to evaluate any other items that JoeG stated above. The requirement on the installation of the door is based on 18.104.22.168. only.