LOOKING FOR AN ARGENTINE 1909 CARBINE MAUSER EXPERT

Hi Guys

Need some help please. Please identify what this may be. It has all the proper marks and is dated 1912 by the its serial number. Everything seems to be in proportion. The length of the cleaning rod etc.
I’ve also included a photo of what it should look like.

Last night I bought this Argentine 1909 Mauser Mountain Carbine online from what I believe is a reputable gun shop.
The photos just don’t add up. Also the barrel is 17.5”. Any research I’ve found the barrel is supposed to be 21.5”
If you look at the photos, there is supposed to be a portion of the barrel visible behind the front barrel band and there is not. The wooden hand guard begins immediately.

I have found some info where there are 2 or 3 variants of the Mountain/Engineer model but with no details.

Looking for some factual information or a source that might have it.

Thanks