Just received a UFH bayonet. It does NOT have a date but does have the flaming bomb on the tang and UF, but NO date. However, the guard does have some numbers stamped into it. The scabbord also has the flaming bomb. So how do I know this is WWII vintage? It is NOT the 16" blade length. Otherwise, it's a very nice piece and the fellow who sold it to me is a super nice guy, so I really have no reason to doubt that the bayonet is not authentic. Help please! Thanks.