How many units can a new factory produce?
According to the Wikipedia article Comparison of Axis &amp; Allies games, some versions of the game had that restriction and some didn't have it. 


  The number of units that may be deployed in territories with Industrial Complexes per turn varied depending on the game: in Classic and Pacific, Industrial Complexes that were held by the player at the start of the game (including those that were lost and subsequently recaptured) allowed an unlimited number of units to be deployed, while captured or built ones were able to deploy units equal in number to the value of the territory (to a minimum of 1 in Classic). Revised simplified the rule to all Industrial Complexes' production being limited to the value of the territory.


Checking a few different versions of the rules I was unable to find any that removed the IPC rule completely, however they did move around where they list the restriction. Some versions have it right under the Mobilize New Units heading, and some have the restriction under the subheading Restrictions on Placement.

Regarding your specific version, I was unable to find that version of the rules. However I did find the 1986 version which also has the 4423-X1 serial/catalog number. It states on page 21, under Section 7 Place New Units On Gameboard:


  Other considerations:
  The production capacity of industrial complexes: Original complexes (ones you started the game with) give you unlimited capacity - you can place any number of newly purchased items in a territory with such a complex; new complexes (one you purchased and placed or captured) give you limited capacity per turn - the number of unites you can place is equal to the income value of the territory the complex is in.