Several questions have come up in the past about the various Boy and Varsity Scout hats and which ones are "official". Here's the answer, along with color illustrations from the present and past Supply Division catalogs which show these hats.
Basically, any hat which the BSA has created for wear is suitable for wear by Scouts and Scouters at any time with any uniform. There currently exists eleven different official hats created by the BSA. This does not include official headgear designed for various National and World Jamborees, National Order of the Arrow Conferences (NOACs) and national program emphasis -- all of which may be worn with any official uniform. Types of headgear range from the "smokey-the-bear" Campaign Hat from the 1920s and onward to today's "Indiana Jones" felt hat, Official BSA hats have the BSA's seal inside or on a tag attached to the hat.
For Scouters working with a Boy Scout Troop, a Varsity Scout Team, or Venturing units, the TROOP, TEAM, CREW or SHIP's YOUTH LEADERSHIP determines the hat style for wear. We adults would love to tell the youth what to do, but it's THEIR UNIT, and therefore they make the decision on the hat style (andneckerchiefs, for that matter).
Once the unit's leadership decides on what it's going to wear, then the next thing is to decide to go with official BSA hats (preferred) or a commerical hat (cheaper but not preferred). Your unit's financial state will determine which hat or what style of hat to wear.
Many of these hats are no longer sold through the BSA's Supply Division. I've been told that basically there's a ten-year shelf life on most BSA uniform items. You may be able to obtain these hats (and some others that I don't have scanned here, for instance the Explorer field ("flat" or "garrison") hats worn between 1958 and 1975 or so) from second-hand stores, auction houses, resellers, memorbilia collectors, and the like. The Supply Division only maintains in CURRENT STOCK the hats shown in the most current BSA Supply Division catalogs. However, as I've wrote below, there's that slight chance that some of those hats are "found in a box in the back somewhere", and are made available to local Councils for "liquidation sales" or made available for general purchase.
Commercial hats can be obtained through the BSA's Supply Division, using theirCustom Design catalog ; or from a number of local and regional companies that deal with creative hat designs. Firms which create distinctive hats for your unit incorporating one or several of the BSA's official indicia MUST be registered with the BSA's Supply Division. Please consult your local Council before signing any kind of contract with a local or regional company, because only local Councils can enter into contracts with companies. (source: BSA Rules and Regulations; BSA Fund-rasing guidelines).