I disagree. The metal you collect is not related to the number of fakes (there are fakes in all metals) but more in the price bracket you plan to buy. When I started, relatively fewer people cared about late Romans and beginners bought more denarii of the first three centuries. Today this approach to the hobby would cost $20 to $200 for common things and $200 to $1000 for 'better' things (nicer coins of 'name' emperors like the 12 Caesars). If you choose this track I suggest using trusted dealers which is exactly what I suggest if you are buying late Roman bronzes anyway. If you must center your collecting on uncleaned lots, you will be buying bronzes and you will be buying from sellers that neither know nor care about the individual coins. Certainly there are better bronzes and better dealers dealing in the late Roman period but most new collectors impressed by how cheaply they can get old coins learn mostly about the late bronzes rather than the early silver. Buy into the phase of the hobby that you can enjoy and afford. If you see no problem spending $5000 per coin, attach yourself to a trusted high end dealer and ask to see bargain gold. Collect what you like, not what we tell you or what we collect. I collect everything (except gold just because there are none in my bracket) which is why I know a little about many things and a lot about very few things. Real experts usually only collect a few things.
For many years the most common fakes were whatever coins were in demand most by people who know little or nothing: Athens owls, Tribute Pennies, Caligula, Nero, big Greek silver. The safest coins from a fake sense were things that are hard to sell in genuine (so why make fakes that won't sell either?). What amazes me is lately we see fakes of late bronzes selling for more than the coins they copy but that is another story.