Joe,
Boyer had his construction technique, mainly the hulls get their strength from the bulkheads, thinner foam. These were the Boyer Mark....up to V. You could get Kevlar outer skin with either 1) glass inner skin, 2) carbon inner skin, or 3) Kevlar inner skin. The choice was up to you, and you could also get Al or carbon beams. Also, boards and rudders could be either carbon or glass. You could therefore get a boat with quite a range of $, depending how you ordered it.
Flyers were not built in enough numbers to satisfy Aus, or US, so AHPC (Boyer) contracted to build the boat for those markets. The build was stipulated by the designer to be thicker foam so the boat gets its strength from the skins and not the bulkheads. There were no options on the construction...carbon, foam, then Kevlar outer. Also, no option for Al beams, carbon only, as well as only carbon foils. He designed (copy) the Mark V to be as close as possible to the Flyer underwater (if you can not beat them, join them). Above the water the boats look different.
Because the Flyer was so popular, Boyer stopped making the Mark V (he did not get any orders for 1-2 years). Last we talked he was working on a new design, but AHPC has gone through some changes recently.
Hope this helps,
Ken