Hey Grub,
Not sure which pen the American fountain and rollerball is but if it's the one with metal to metal threads (Woodcraft #123101), I would try to sell a few before buying more.
When I started turning pens I made a lot of Sierras, Atlas', and the "Classic American Style Rollerball" Pens.
The Atlas and Sierra pens turned out to be very popular but the American Style pens didn't sell at all, and I still have all of them today, several of which are being used around the house and shop!
When you place them next to other kits such as the Barons or Jr Gents, you will see why they aren't good sellers! After a few times taking the cap on and off and posting the cap, the metal threads start scratching the black coated parts and they look horrible.
This is, of course, just one persons opinion!