thers a lot you don't mention here. Do you have a heli IR? have you met the currency requirements? is the heli certified for Instrument Flight? is your /G on the flightplan an IFR approved GPS with the necessary paperwork? and in which country are you asking about? do you have the necessary approach plate available when they give you a clearance? is the weather above minima for the approach? what are you going to do when you can't get in?
in short - can you legally accept an IFR clearance? but forget "can I ask for " - you are PIC, you can ask for whatever you need. And, most likely the controller doesn't havea copy of yoru flight plan in front of fthem and couldn't care less what equipment you filed on it.