The radiation pattern is more 'out and away' than what the AP-205 has, so they are not the same patterns (TL;DR the AP-205H has a much larger null 'behind' the AP)
Heat loading on the AP will add 10-20C to the internal temp, depending on load. Where will the NEMA be mounted and what will the ambient temp outside of the NEMA be? Will the NEMA be exposed to the sun?
In general though, it's not recommended to put indoor APs into NEMA boxes due to internal self-heating (regardless of indoor AP model). The 205H has heatsinks that they other APs do not have because it is a physically smaller package so the backside gets hotter than the backside of an AP-205. Additionally since the AP-205H can supply POE out, it can generate FAR more heat than a regular AP-205 (assuming that is being used).