At this juncture, to all Star Alliance members, CO and UA are still pretty much entirely different airlines, definitely as far as other FFP programs are concerned.
There are other examples which show the continued differences. For Domestic F seats on UA metal other Star Alliance carriers book a seat in 'O' and you therefore pay the First Class price. For CO it's 'I' and you pay Business Class price. So UA/CO haven't even sorted that out yet. They remain separate entities as far as awards are concerned.
As I said above, until UA and CO are one airline in all areas, and inform their Star Alliance partners that they are one airline, with one set of rules, these differences will exist.