As I understand it, it's a baffle to reduce vibration in the lines. Because of the baffling, it's supposed to be very difficult to flush it. The solvent and the junk get hung up and can't be removed (or at least that's the theory).
I don't think I'd worry about it unless again, you had a catastrophic compressor failure or your oil is so contaminated with water and junk that the whole system needs to be flushed.
Pull your orifice tube first and that will give you a very good indication of what shape your system is in.
When I did mine, the old orifice tube looked good so I elected not to replace the evaporator or condenser or flush the system. It's working great (of course your mileage may vary as each system is obviously unique).
If you don't mind spending the money and want to dig in to a full A/C rebuild, I'd replace everything; high pressure hose, evaporator, condenser, accumulator, orifice tube, o-rings, liquid line, compressor, etc. I think when I priced everything at Rockauto it was under $500 for the parts.
You probably don't need all that, but you'd have a brand new system! I elected not to do that, because I figured worst case, if I needed to replace something later (say a condenser), the system only takes 24oz. of refrigerant. In the future, I can repair the system if I have to for only the cost of the part, a little time, and $20-$25 worth of refrigerant (although any time the system is opened up, you should replace the accumulator which is $25 at Rockauto.