Agree with the above posters than a half isn't necessary in the 2 months before. It is helpful to have some sort of tune-up race (10-mile, 15k, or 10k, in order of preference) so you get a directional indicator of where your fitness is relative to prior periods.  I'd be reasonably confident in calling a reasonable MP off one of these races, especially with some points of comparison to prior races.

Also, if you've had  good training cycle, the tune-up race can be a great confidence builder.  But if it requires a lot of travel that you wouldn't do except for the race... not really worthwhile IMO.