Assuming that official
Rome mint issues are not only of proper
style, but also on full-sized, round flans with
well centered strikes, then the vast majority of Claudian
asses I have seen, or that you see for sale on websites, are not fully official.
This would match what people like Duncan-Jones have written about bronze coin shortages of the time and coin distribution.
So, unless you paid a premium for a specifically
Rome mint coin I would not be worried.
SC