L fares earn 50% on CO (T's earn zippo) so I would credit to CO to insure you get credit for at least some of it. They are merging CO and UA accounts at the end of the year, so your miles will be combined then, or if you link your accounts, the miles can be transferred instantly.

You'll get 2050.5 miles and EQMs for the 50% of that one way versus 100% of the 339 between PRG and DUS.