Mossberg 895 Mag? 20g

Mossberg 895K ?

 Well, that is what I purchased it for, but it does not quite seat or work in my early model 895 bolt action 20g. 
It appears a bit short in the mag well, at first glance it looked “right”.

It is NOS. 
It appears to be for 2 3/4 inch shells only due to its size? 
There are a couple comparison photos from my 2 3/4 - 3 inch magazine. The circled one is the one that is for sale!

Anyways, the price is firm, i’m just trying to get my money out of it again. So i can get the  correct magazine. 
You pay the postage :) 

Thanks for looking!