Yes, it is possible to fit the CBR250R's Red fairing to the CBR150R. Both the bikes are built on the same chassis and comes with the same design of the body fairing.
You can match both the bikes externally also as the bolt being displayed on the fairing is located at the same position. The indicators and the air intake vents are also exactly the same for both the bikes. You can use the fairing of both the bikes on any one of them. The company uses different shades to differentiate the models as same shade on both the models would effect their marketing strategy.