Exaggeration
By buying directly from family...
Photo of the cavalier!
Usually it is very helpful.
Especially when the bar has some irregularities or distinctions (ribbon folds, incorrect sequence of awards, etc...)
+
Medals "fitting-in".
Medals that were in the bar for 70+ years should have something in common
+
General "realism" of the bar
Of course professional could make very realistically looking bar (by using original (very simple one) as base).
Fortunately
a) not very much professionals around
b) many of them are too damn lazy
c) creation of high quality fake japanese bar is not very profitable business (if it's not a Togo bar of course )
Regards,
Nick