The m48 is an intermediate action m98, the k98k is a full length action m98. That’s the main difference. The handguard and bolt handle are different too as pointed out. The m48 handguard clips onto the barrel like other Mauser m98’s with that style of handguard, the little screw isn’t what is holding it on. It’s easy to break if one isn’t careful when taking it off. The m48 was basically the old Yugoslav m24, which in turn was a licensed copy of the FN m24, which had a flat butt plate straight bolt handle etc. but that same intermediate action. The m48 added the later cup buttplate of the later k98k as well as the front sight hood and German cut through sling arrangement. The later m48a has some pieces stamped instead of milled. The hole in that k98k is for the Gew. 98 style detachable sling swivel, it was for parade use as you’d take the swivel from the buttstock, put it in that hole and put the front of your sling on a little hook on the H-band. As the k98k didn’t use that arrangement, that particular piece is probably from an old Gew. 98 or Standard Modell.

The correct triggerguard on the Kar98 should be one without the hole. That is possibly from a pre-war "Standard Modell" or WW1 Gew98. They are actually quite useful when paired with an old '98 with the under the wood style detactable rear sling swivel. When time allowed, one could unhitch the rear swivel and attach it to that small hole, and shorten the sling length to fit tightly around the left arm, just above the elbow, to give a very rigid hold for more accurate shooting.

Is your K98 all matching? Nice find if it is. The Yugo M48 is probably all matching ,

Love all Mauser rifles.

The yugo m48 is a slightly crude copy of the FN model 30 The yugo m24/47 is a straight up copy of the FN model24 So much so that Yugoslavia was originally buying model 24s from FN Until domestic production started. And the early 24/47s are incredibly nice rifles the one is have is butter smooth and very well finished with very fine machining The m48 is just a notch below finish wise and is rougher cycling….. There is no means of bolt disassembly on yugo mausers…. They went so far as to omit it from yugo made k98 stocks when they rearsenalled the k98s they had And almost every single piece of a yugo rifles will interchange to a k98 except for the stock The trigger guard. And bolt body And firing pin Everything else like sights Barrel Action screws Trigger assembly And safety, cocking piece and bolt sleeve and I think even the extractor claw will swap onto a k98 bolt. Barrel bands from 24/47s will swap but I believe the m48 bands might not because of the stock dimensions being overall thicker but I could be wrong there.