Problems with this film.

"In those days"! Hey, please, hugh1971, as one Hugh to another, I saw this movie in the theater and am not THAT old!!

But your point is spot on, they took no real care in those crowd scenes, so long-haired Indians and Brits and 1970s dress were rampant throughout, much of it simply because they just filmed scenes without making the effort to make the people and things in the shot appear period-correct...something which many films before, at the time, and since do right -- and many others still get wrong.

So it wasn't merely a question of "those days" (here, 1980). Hundreds of films, going back to the earliest days of cinema a century ago, made major efforts, very often very successfully, to "look" genuine, in clothes, hairstyles, cars, whatever. But of course many failed, though sometimes only in small ways. I often wondered why some filmmakers think the audience won't notice background things that may be inappropriate to a particular movie, like modern cars, TV antennas in the 1860s, dress and above all hairstyles. (Your catching the incorrect style of these guys' pants was amazingly sharp!) And this is apart from many films whose dialogue uses modern expressions instead of something from the era depicted.

No, not only the "look", but the "feel" of THE SEA WOLVES just didn't do much to make you think it was 1943, and this is a big problem. But still an enjoyable movie, maybe in part because of these flaws. "A geriatric 'Guns of Navarone'", as it was often called upon its release.