Mine is a normal '14 X1 35i, stock gauges. I think the 28i's have mpg on the lower right though instead of oil temp.
I think there have been some people on the various forums though from back in the day who have swapped clusters or something for this very reason either on e9X 28's or on 128i's retrofitting 135i clusters. So I think it's doable, may just be a pain.
Here's one such thread:
https://www.1addicts.com/forums/show....php?t=1462928