You are confusing wet and damp locations. Shower type trims are for shower type environments which are considered wet locations. Open baffle trims are ok for damp locations which the underside of a porch roof would be. This is perfectly acceptable as far as the NEC goes.
Damp or wet location aside, I would think that you would want to close off the recess light to help keep the bugs out. If the trim/housing was open, bees, etc. will get up through the housing and build nests in side the eaves.
Seems that if housings are listed for damp location, the trims wouldn't matter after all.
This is off the Halo site, and a typical can. Be safe and check the listing of the fixture housing.
Installation Features 7 1/2" height allows use in 2x8 construction. Housing adjusts for ceilings up to 1 1/2" thick. Shipping insert protects socket from paint overspray. Listings UL Damp Location UL Feed Through CSA Certified IP Rated
[This message has been edited by russ m (edited 12-31-2003).]
progress makes an open shower trim. P8072WL-28 metal flange which utilizes a par 30 50w long neck type spotlight. trim has a seal in the top. in one local county i work in, one of the ahj's would not accept the app (listed) while another (in the same county)would accept it. the latter of the ahj's passed because of warning lable stating type and size of lamp required. go figure ken m