Yes, most of the time join exercise is appropriate, but without radar on.It will definitely happen. The US has already exercised with Su-30MKIs from India as have the Singapore Air Force. There's not going to be a lot of difference between the MKI and MKM so the benefit to USAF pilots is less. The benefit to the RMAF is a lot more as pilot training is improved via flight experience against pilots who probably have significant actual combat experience.
However, If not mistaken, Indian shown their Ks not MKIs.