No, some are still Y. There are two types - capacity controlled and unrestricted. Capacity controlled book into various midrange coach buckets depending on carrier; unrestricted book into full Y and have "last seat" availability. Both types can be changed without penalty, but for the capacity controlled, space must be available in the capacity controlled fare bucket. If there is no such space, you must upfare to a Y (but no change penalty). Some carriers (like UA?) restrict the ability to Y-up using the unrestricted fares, but they still count for 150% EQM bonuses and high priority for upgrades.

CO does not have the contract for DCA-IAH - AA currently does (have to connect in DFW). CO has very few, if any, government contract city pairs these days. People who fly CO on government business usually are flying on regular (i.e., non-government contracted) fares.

In any event, I have had several surprising five-day EUA's this year on DCA-IAH-DCA. Friday afternoon flights still have 70% elite passengers, though.