Hello Brad,
The story behind the "namban" or "southern barbarian" armor is quite an interesting one. The namban period started around 1550 and was the result of Portuguese influence on the Japanese arts. The Portuguese brought not only bible-toting missionaries but introduced firearms and western style armor. The Japanese adapted these suits of armor to their own taste, lacquering, adding items of Japanese origin, copying of course and so on. The western breast plate were better protection against musket balls and the western style suits were also seen as a sign of wealth by the high and mighty, such as the shogun and his peers. You will see that the Spanish style helmet is worn back to front, again a Japanese idiosyncracy! OK I stop ranting, but anyway, to answer your question, some of these suits were indeed gifts from western dignitaries before Japan went in a almost complete lockdown from the outer world, but many were local made copies.
cheers,
Piet