I assume then, there is no way to get gsx to not spawn the front air stairs when taxiing to the gate from the runway and that there is also no way to make a profile specific to one livery.
Rather than not being possible, I don't think it would be even useful because, as I've said, just because you have an integrated staircase, that doesn't mean you'll always want to use it so, even assuming we did something like you are suggesting, it would mean you would always *forced* to use the airplane stairs with that airplane, no matter what, which is hardly realistic.
That's because the way the 737 is made, it always let the pilot *choose* if using the plane stairs, it's not like other planes like the CRJ or similar, that when they have stairs, it's embedded in the door, so you never use the airport stairs.