They were originally produced without them 1935-1939, but switched to including them in 1940.
Russian Capture K98s had theirs removed, but they can be re-added relatively easily.
Starting 1941~ and later all had a front hood. keep an eye on the stock. Bubba changes the stock with cupped buttplate and place earlier receiver is give away.
If the front sight has slots, then you need a sight hood. Some early rifle were altered for a sight hood afterwards.
Erma (WaA280) had often wider sight hoods, bnz more rounded shape (rare as moon stones). Bcd sight hoods have a strange shape were they clamp. Then there are also straight sight hoods. Anyway, all sight hoods are rare!!
If you try to buy an original sight hood, when you pay $40 on Ebay or $70, you'll probably end with a reproduction or post war produced Mauser sight hood.
I still have some original sight hoods, but these are not a bargain.