Originally Posted by
trooper
Just a guess here...
I'd suspect there may well be "codes" for diffrent menu choices within the Special Meal categories.....
..but that the codes are for UA's catering system to use in ordering.. NOT for pax to make more specific choices...
As I said.. just a guess!

I request a gluten-free meal when I can, which is not a common request, and some of the CSR haven't encountered it.
I usually request it as "gluten-free GFML", since, at least in the past, it was entered as "GFML", and this made it easier for the CSR. Meal codes, such as GFML, are used across airlines.
--Bob