I think what you read was in reference to the UK Typhoons, The MoD decided to save around £90M and not have the gun fitted to the 2nd and 3rd tranches of Typhoon.
But apparently the FCS needs the weight of the BK27 to work correctly, a proposed answer was to fit a fake canon!!, but it had to have the same weight distribution and g tolerence as the gun.
Now it would have cost quite a bit to produce this lump of metal and get it flight tested... it was found by the bean counters that a real BK27 is an exact match for a BK27!!!.
So real ones will be fitted, and the RAF have promised not to use them;-).
I think the concrete reference is Tornado related and refers to the Portland teams 'Blue Circle' radar!!.
Cheers