Wow -- that is a great one!
Regarding the time period, most of the ready examples seem to be from the second half of the fifteenth century, (excepting the Parisian Tarot card), but I doubt that the notion was limited to that period. Street performers and court jesters used animals routinely. When more exotic animals were unavailable, a dog might just as well be dressed up, as shown in the famous Bosch Conjuror copy.
The Magician
http://www.wga.hu/html/b/bosch/1early/11magici.html
As was probably mentioned earlier in the thread, several of the images at the goochelaar page appear to show monkeys. It is difficult to be sure with the small images, but these three appear to have monkeys.
http://home.tiscali.nl/jannesdegoochelaar/afbeeldingen.html
De goochelaar, voor 1490, tekening, Hyronimus Bosch, Herkomst onbekend
Luna's Kinder, ca. 1466-1470, gravure, Meister des Hausbuches
Luna's Kinder, ca. 1470, houtsnede, Herkomst onbekend
Regarding the question of whether the artists would know what monkeys looked like, consider this comment about a Durer print of the Madonna with Monkey -- seriously!
"The Italian influence is manifest. This species of monkey was a popular pet in the fifteenth century. It appears also, obviously based on the same lost preparatory drawing, in Dürer's painting Christ among the Doctors. The monkey, at the same time, was a symbol of lewdness, greed, and gluttony, commonly associated with the Christian concept of the Synagogue and more especially with Eve. The "Island Abode" in the background is based on a drawing."
The Madonna with the Monkey
http://www.wga.hu/cgi-bin/highlight.cgi?file=html/d/durer/2/13/1/021.html&find=monkey
So it doesn't sound like monkeys were any kind of rarity.