Am discussing acquiring a helmet from a seller. I could see modern chin straps had been added. I would want it to stay on my head well. I asked for shots of chin strap retainers. Here's what I got. Obviously these have been on for a long while. are they original? If so, when did they change from the ones I know they used. 

Here's the shot.

 

Here's a shot of a retainer on a helmet I own.

 

You helmet with the lugs for the chinstrap is German, either model 1916 or 1917.  (actually there was never an actual model 17, that's a collector term designating the metal liner band from the earlier leather liner band. ) The other helmet is Austrian, and takes a different kind of strap.  The strap on the Austria is certainly not original to the helmet.  Almost looks like nylon.  Austrian straps were mostly a canvas strap with leather fittings. 

 

Steve  

As themick said, it's an Austrian helmet with replaced strap.  A desirable helmet IMHO.