When working with material that is mis-dated in the imprint, catalogers are reminded that the correct date goes in the 008 and the mistaken date goes in the 046, even though Alma currently does not index the 046. (http://www.loc.gov/marc/bibliographic/bd046.html)
For example:
Imprint reads: London: Printed by John Smith, 1970 [that is 1790].
- 008 should be coded 's' and '1790'
- 046 should be coded "$$a x $$c 1970"
For almanacs that are dated the same year for which they are issued, correct the date to the year prior, though add a question mark due to the conjectural nature.
For example:
Oxford almanack for ... 1690. London: Printed for the proprietors, 1690 [that is 1689?]
- 008 should be coded 's' and '1689'
- 046 should be coded "$$a x $$c 1690"