Those euros from the early sixties were pretty shoddy.

They didn't lack security features, they just had less of them. The old bills still uses blue and red threads scattered throughout the cotton/linen blend for paper, and utilizes Intaglio printing to give it its unique look. Nowadays there are more security features on currency, still with all those features a person only needs a few seconds to pass off a counterfeit.

If you are worry about being fooled into receiving a counterfeit note, the best thing to do is take your time receiving money. Know what a real and a counterfeit note looks like. If it is smooth with a magazine or computer jet printer look to it, it's counterfeit. Counterfeit detector markers don't always work. A counterfeiter can strip a one dollar bill of its ink, then print over it to make it look like a hundred dollar bill. Since the bill was at one time real currency it will pass the counterfeit marker test.