Dan Howard's point is well made. If one culture adopts the other culture's gear, it indicates admiration, at the least. If the gear which is imitated is not of practical significance, it is likely merely admiration - for example, the US military used kepis in the Civil War era, in imitation of the French. After the Franco-Prussian War, dress uniforms in the US use Pickelhaube type helmets instead. Of course, in the 19th century, headgear didn't provide much battlefield protection.

In the theme of this thread, when the Europeans reached Asia in the 16th century, neither side adopted the other's swords. However, the Japanese did adopt (to a limited degree) the European style of plate armour, while the Europeans never used lamellar. More important, neither side adopted the other's bows - but the Japanese seized upon the arquebus/musket with great enthusiasm, such that the yumi becomes much less important by the end of the Sengoku era.