U think US allow?
Kunal, US doesn't have many options. For example, IAF refused to sign the CISMOA and LSA agreements on the P-8I and C-130J and instead asked them to install Indian-made sensitive equipment on board by BEL. If the US had been adamant on pressing us at that time, it would have simply lost the contract to some EADS or even Russia (maybe JV or some already existing model to be modified). Lockheed Martin and Boeing both couldn't afford to lose contracts upwards of $8 billion especially at this stage.
IAF with their new chief has been strong and vehement when it comes to no-nonsense; something which we didn't see during previous air chiefs. ACM Naik has already conveyed many times that he assuming power means business and not stuttering around. I doubt that US can push us too much around or end up losing contracts to Europeans, Russians or now into the coming decade even local players like RTA project and MRTA.
Hence if US can be pressed to install BEL-made communications equipment instead of their own, I don't think that there would be any problem for them to allow us installing BrahMos. Only thing is that NAVY will have to be a bit more like IAF: adamant and aggressive.
Remember; Lockheed Martin had great hopes from IAF and IN when it came to "may offer F-35", which all went down the drains when MOD issued an official statement that it won't concentrate on a 3rd stealth platform. That's a big blow as they were expecting an easy money from our otherwise-weak-for-US-magic politicians.
But thankfully better sense prevailed.