The third "safety" lug on Mauser 98 type actions generally doesn't bear against the receiver and thus doesn't contribute to action strength. Its purpose is keep the bolt from being blown out of the receiver in the event of the front locking lugs failing. Some actions use the root of the bolt handle to accomplish the same purpose.
You are correct. This is one of the fundamental differences between the 'Commission Rifle' Gewehr 88 and Paul Mauser's Gewehr 98.
Here is a link to my photobucket main page, on the left you will see a album titled "Gew 88". I have taken some detailed close up photos of my Gewehr 88 and a few of them center on the action of the Gewehr 88 and comparing it side by side with my Polish Kbk wz 98 carbine which has a Mauser action.
My photobucket page
We need more info and threads about Gew 88's on here. I hardly know a thing about them but the one I have is beautiful. I have never shot it and apart from the turk marked bolt, arabic rear sight and german unit B10RR250 marked on it, I really know nothing about its history and development.
I recently bought a book called "The German Gew.88 'Commission' Rifle" by Paul S. Scarlata. It is jam packed with information on the Gewehr 88, its development, along with its limited service life in Germany as well as other nations. The book even covers the Gewehr 71, 71/84, and the Kar.71, 88 models. It also has a section on the bayonet types that were issued with the Gewehr 88. I learned alot from reading this book and I highly recommend it if you are interested in the Gewehr 88.
As far as your regimental marking, it is very similar to mine on my rifle. Using the following source (somewhat incomplete) (
Link), I would say your rifle at one point, was the 250th weapon, attached to the recruiting depot for the (a ?) 10th Bavarian infantry regiment. The book reference mentioned above does not cover regimental markings in detail so I had to do some searches on the internet and post on other forums to get an idea what the markings on my Gewehr 88 meant (mine, as you may see from the photobucket page, was attached to the recruiting depot for the 95th Landwehr Infantry Regiment, rifle # 325).
I am curious do you have any more markings or "X'd" out markings on the front and/or rear band ?
Hope my sources help you out but feel free to ask anything else as I may have the answer or would be interested in finding it.