Right, those are definitely not right. I wish I had an RAL colour chip set to find exactly the right one- but then judging by the coloration on my LW ammunition, the yellows did vary somewhat- but none is like that odd light yellow on the Finnish shells.

I had one of these once myself and remember the '20' stamped on it so it would have a larger '20' in black ink near the top (it's the explosive filler code), and there'll be dates of manufacture, filling as well as maker codes and the abbreviation Przugz (since it's a drawn shell), but you'd need to find someone with one of those controlled splinter type shells in original condition to know just what exactly would be correct- they varied with type and manufacturer likely; mine is a different type so what's there won't help. And my only case with original markings is a Pzgr so is different than the Sprgr with respect to propellent weight.