Is this the correct procedure?
Surely not.
That's a very convoluted way to overcome the previous inability of GSX to read encrypted airports from the Marketplace, but even if it MIGHT work in some cases, it would never work everywhere, because it really depends how much the add-on airport changed in relationship to the default.
After the October 17th, where support for the new Navdata API that came with the SU10 SDK has been added to GSX, the proper way to use Marketplace airports, is just enabling the usage of the Navdata API in the GSX Config panel, so GSX will get data about the airport through Simconnect, without any need to find and read the actual .BGL file.
Enabling it results in any reference to the airport .BGL in the .INI file completely redundant, you can leave it there or remove the line altogether, it won't make any difference, since GSX won't read the airport .BGL anymore, it will just load an .INI based on the ICAO, that is the first part of the name.
However, this also means you need to be sure the .INI you have for that ICAO is really made for that airport, since without any reference to a .BGL (this is how it works using the Navdata API), GSX won't be able to automatically associate the right .INI to the right scenery, in case you have more than one for the same ICAO, so it's just easier to be sure you have only one .INI for a particular airport, and it's the correct one.
Now, it's difficult to say if THAT specific profile you are referring to will work well or not. Again, it really depends on the airport, because if it was intentionally made to force GSX to work on a Marketplace airport when it couldn't, so it was edited using the default parking names and positions, altering their positions trying to match the airport.
It might have issues in case the parking names loaded by GSX, which now (when using the Navdata API ) DO match the actual Marketplace airport, so they might not match the ones in the profile anymore, which was made by repurposing the default airport.
So, the first thing I'd try, is to enable the Navdata API first, so GSX can read the PROPER airport data from the sim, and not use any profile, see how it goes.