I’m far from knowledgeable on these but my late F block 43 blm has an unmarked lever. Looking around when I got it, this appeared to be completely fine. Maker and letter block will be pertinent to whether or not yours should be marked however.
Do you mean a G41(W) Walther trials rifle or a G41 production rifle maked ac or duv? The safety on my G41(W) #4641 is numbered and proofed.
Chuck