A pat on the back if you can tell me what this is...

Ok, so i was at a gun auction today and found this sporterized mauser, which i bought for $200. I originally thought that it was a gew kar 98a. It was labeled gew 98, as you can see in the pictures, it had a curved bolt and it is short enough to be a carbine. It is also stamped Amberg 1917. Great right, the only thing is that all the information i have found on the subject states that Amberg didn't make a carbine version of the gew 98 in 1917, as they stopped production of this rifle in 1911. This led me to believe that someone put a short barrel on the gun at some point, but when i looked at the numbers on the receiver and the barrel they were the same (meaning the barrel goes with this gun). My second thought was that someone cut off the barrel, but the sight on the gun is a 98a sight (i think but thats why i included a picture of it). From what i understand the barrel on a 98a is 23", so i measured the barrel and from the tip to the receiver is 22" with one more inch being in the receiver bringing the overall barrel length to 23". So what’s up with this? I would really like to know. My only fear is that it is a gew 98 with a cut down barrel. If you could give me any history about this gun I would love to here from you too, Thanks.
Here’s the pictures and the numbers on the gun:

On receiver:
Top: Amberg 1917, with crown on top
left: 4841
right: B A O with crowns on top of all

also "Gew. 98."

On the Barrel:
Top:7,91 and an "S" by the sight
left: 4841 and 8mm
right: "S/42G", "[P][74]", "[k][155]"

I can also make out a Crown and an "A" on the stock