The M48 trigger guard screws are the same as those for the standard Mauser 98.
Permit me a comment on fitting those screws. Those screws were made to snug up tight with the military stock. When you replaced the stock the screw bottomed out in the receiver before it properly clamped the guard and the receiver. When you kept trying to tighten it enough to fit properly, you snapped it off.
So when you get the new one, first, without the stock, make sure the trigger guard fits properly on the receiver. Make sure the screw tightens up OK. Then inlet the stock so the trigger guard keeps the same relationship with the receiver. Don't depend on the stock screw to crush 1/8" or more of wood. If the screw is too long, then grind some off the end of the screw. Keep doing this u until the screw fits and snugs the stock down without bottoming out.
If you plan to do that kins of stock work very often, buy a set of try screws from Brownells. They have "T" handles and are a lot easier to work with than the original screws.
Jim