I would also think it would be very difficult to make a counterfeit version of these "bars" because of the scoring and how easy it is to break them apart. If I understand how counterfeits work you need to put something on the inside that will make the bar weigh the correct amount. All you would need to do is break one of these bars in half and if something was inside you would see it. It would be very challenging and probably not worth the effort to make every single 1 gram piece have their own counterfeit interior weight (...)
well, I have to give you that one - it seems to be more time consuming to counterfeit this one, than a coin - although I don't think it would put it into "extremely difficult" territory. You can sandwich 50 little tungsten petals, and it is more laborious & time consuming than to sandwich one tungsten disc (but I suppose, you can automate it pretty well), but it's not really that far fetched. Definitely worth it, if silver coins are worth counterfeiting now.
There are also other factors to consider: with coins, you have intricate design, that have to be replicated as well - here, there's nothing like that. When one counterfeits coins, legal tender laws apply, and he will be going against the Secret Service, and the punishments are really tough as well. With these - you are "just" a regular crook/conman.
If anything, there's lower probability they will get counterfeit, simply because I suppose there's very small demand, comparing to coins, so why would anyone bother to counterfeit them.
on the other hand, what is the probability of getting a fake coin, if you buy from reputable seller - I think it is very, very low...
Lastly - buy yourself a Krugerrand, and do a "ping" test on them - you'd need to be completely deaf, to miss that pure ringing from them

. I don't know how it works for Eagles, though. Most definitely, wouldn't work for these breakable bars (pure gold, it will rather make a "thud", than ring

)