That was not a gut hook on the other knife, that was a "line cutter".
You use them to cut line and cord, it is sharpened on the inside radius like a gut hook is. Even so, I do not like them at the base of the blade like that, as I am of the opinion that it will weaken the blade there, and if the blade breaks that is where it will snap. I prefer the line cutter to be on the back side of the knife towards the tip, it makes a stronger blade and if it does break you still have somethng useful and not just a handle.
OK Mack The Knife, here is a design I would envision for an IFG knife....
I didn't put dimensions, but the blade length is 4", blade width is 7/8" (22 mm?) and thickness is 4 mm. Handle is also 4" but anything from 3 1/2" to 4 3/8" would fit proportionally. I saw your comment about not wanting a guard so I left it out, otherwise there might be a small guard that extended on the bottom and top 5mm or so.
The lanyard hole is made from 10mm tubing. I like a lanyard hole but do not keep a lanyard attached to anything, if I need one I'll use a piece of cord. A large hole is a lot easier to fish a piece of twine through than a small one. Also note it fits into the upper handle radius, when you use a knife with a lanyard where you actually NEED the lanyard you want to keep the lanyard loop small so if the knife slips from your grasp it does not move far and you can grab it back easily. If that upper corner is not radiused that corner always bumps you in the wrist and is a distraction at best, at worst if you have to use the knife for a while it will chafe a red spot on your inner wrist.
In regards to finish, since these may not be made in the most sophisticated of places a great finish would be sandblasting and then bluing, and then the handle made from either a light colored wood, bone, or antler. It would be a striking color combo and also hide any minor surface irregularities in the finish.
Remember those pictures I posted of the knives with mirror finished blades? The polishing took longer than building the rest of the knife did!
Anyway, begrudgingly since you asked this is what I would do. A knife of this size and shape will not only skin deer or butcher pigs, but also the blade is slim enough to clean fish. Of course, it is also a good shape to make sandwiches, which is what I suspect most people will use their knife for!
"What if he had no knife? In that case he would not be a good bushman so there is no need to consider the possibility." H.A. Lindsay, 1947