First year vs first model

"First year" is a label often misapplied by pen collectors. In fact, changes in a given model seldom coincided with the end of the calendar year. In most cases, what is really meant is "first model", as with early Parker 51 pens with end "jewels" and filler plunger made of aluminum (a configuration altered before the end of the first year of full production) and early Jotters with ribbed nylon barrels (a configuration not altered for some two years after initial introduction).