Not quite. 8xxx and 28xx series numbers are used for both SER and ECoR as ECoR too was part of SER earlier. This kind of numbering is common with all the trains from the new zones like SWR, ECoR etc.
17229 Sabari express also has a similar arrangement for PC. The rake belongs to BZA division of SCR, but it gets a PC and a UR coach from SC division. But, Gitanjali is probably unique in getting the coach from a different zone altogether.