The recessed light barrier you mentioned, I assume, is a polyvinyl boot that fits over your existing cans.
This boot is to maintain the vapor barrier of your home.
It , in no way, acts as an IC rated can.
IC cans are used to prevent fires caused by overlamping of cans.
Also, if the jobs needs to pass inspection by an electrical inspector, or insurance inspector, it will be turned down.
Check with an electrician, not an insulator,before doing this installation

If you are using any type of spray in insulation, you will have to replace the cans. Covering them up with anything, insulation or a barrier will be against code and a fire hazard. Since they have no heat sensing device, they will not shut off if they become overheated. IF you are using bats, you can construct a barrier that is open on the top and be sure no insulation is covering the cans. Keep the barrier, which can be a simple plywood box, 3" from the recessed can and any insulation beyond that. This will however leave air pockets throughout your attic for inside air to escape through. If you are going to the expense to re-insulate, it probably is better is use new IC rated cans. Be sure to shop for ones that will handle the wattage you need. Some are rated for 75 and some are 100 and I believe only prescolite still makes a 150. If you must step down in wattage from what you currently use, substitue a par bulb for the R bulb or use the highest wattage R type cfl you can find for enven more energy efficiency. The ultimate in efficiency would be an LED insert for your existing recessed can. These are very expensive to purchase and you will have less light than a standard 75 par lamp would produce. From an energy standpoint, they will pay for themselves over time. You might look at these versus the expense of changing the cans. If you decide not to change the recessed cans, be sure you tell anyone who might buy your house in the future, not to ever cover those exisitng cans with insulaton. Be sure to check with your local electrical code inspector for input. Different parts of the country have different requirements. You don't want to have a problem if you ever want to sell your house. Oh yes, I had a client once who used inexpensive plastic buckets with the tops cut off around his cans as a barrier. If the goal is to have you home as energy efficiet as possible, then change the cans.